MadModder
Gallery, Projects and General => Project Logs => Topic started by: klank on April 26, 2011, 11:02:48 AM
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I hope to post this build as it proceeds, warts and all over quite a few weeks - maybe of interest to some of you thinking of a new project or getting involved with steam for the first time?
I am by no means an experienced model engineer so please be kind if my attempts look a bit ragged compared to so many truly excellent finished works you always see on here.
The text may be a bit basic and simple, but I would hope doing this on a "how to" basis might be of use to newbies and tyros alike.
This is a straightforward horizontal steam "mill engine" kit "suitable for a beginner"!!, together with a vertical fire tube boiler of sufficient capacity to steam it or other similar sized engines.
The engine includes an eccentric driven feed water pump.
The kit(s) have been around for quite a long time, but I have not seen them posted as a build before.
Background
For the last 6 months or more, I have been struggling to build a model "wall" engine - the kitted version of "Rachel" (a German original design) and distributed by GLR. I obtained the castings from Dave Clark (editor of ME) - who had decided not to proceed with it.
Rachel is a B***H - good looking but very fiddly and difficult to understand. (Strangely, it is no longer currently listed as a kit by GLR!!)
It has turned out to be an engine from hell - and I was getting so frustrated with it, that I felt a change of project was in order and to put this nightmare on the back burner for a while..
My dear wife gave me the green light to look for another long term project, so after due consideration, I decided on a more straightforward horizontal steam engine.
I liked the look of the Stuart Victoria, but for nearly the same price, GLR (I had better say here - usual disclaimer) offer both an engine AND kit of boiler parts/plans to make a vertical fire tube boiler all at a usefully discounted price. It is often advertised in the ME magazine, and was the subject of a lengthy build series (both engine and boiler) in the ME by Stan Bray back in 1996/7.
I placed the order with GLR by telephone, and was delighted to receive a telephone call from them the following day to say that the kit was being boxed up and would be sent by carrier that night - "Would I be in to sign for it on the following day?" - very good service.
There was a minor issue in that the boiler funnel tube and two small castings for the top slide bars were not included but would follow shortly. How very refreshing to get an honest deal!!
Sure enough, a large heavy box was delivered the following morning - this is what was inside :-
(http://i336.photobucket.com/albums/n354/klank_photo/Manuals.jpg)
(http://i336.photobucket.com/albums/n354/klank_photo/KitContents.jpg)
Note - I posed this picture after I had done some prelim. work on the bed casting - hence it is painted black (by me) and not in its original - as cast condition.
All of the castings for both the engine and boiler smoke box top are in gun metal and look to be excellent - very little flash/imperfections or unwanted "bits" sticking to them.
The engine bed plate is a substantial aluminium casting - virtually useable "as is".
There is also a handsome mahogany sub-base, ready with appropriate slots for the flywheel and crank disc milled out. This is an "extra", not included as standard - to indulge myself.
The engine has a bore/stroke of 1" by 1.5" and flywheel of 6" dia.
The boiler is approx 8" by 4" dia. (including smokebox and firebox spaces) with 25 fire tubes.
All extra materials, fixings and plans (including two bound handbooks of Stan Bray's engine and boiler build articles) are also included.
Boiler fittings are not included - although sufficient phos. bronze is supplied to make all of the boiler bushes and hex brass for steam/water valves etc.
I will have to turn up boiler flangeing plates from some suitable material. Copper sheet of the correct thickness for the flanges is provided.
The boiler design is based on that published in the ME back in the 1950's - including a weight balanced safety valve!
The boiler may be fired by propane gas or coal (fire bars for the grate are not included although stainless steel and copper for the firehole door and ring are provided).
So, to begin.
There is no particular order to follow in making the engine, but it seems logical to start with the bed.
As I said earlier, the bed casting as supplied appeared very very good - true on both sides after a quick check with a rule held across the faces whilst held up to the light, and no obvious signs of twisting. Virtually no flash or imperfections anywhere.
The supplied plans give dimensions for the drilling points on the various "pads", and the height of the pads above the bed proper, but no basic data as to their positioning nor the overall dimensions of the bed. One must assume that the casting is accurate on that score.
To properly check for accuracy, I used "engineer's blue" spread thinly on a granite surface plate.
Now that sounds very professional - but to disabuse those of you with an eagle eye - my granite surface plate came from Tesco (a food supermarket) - in their "kitchenware" department - sold as a "Trivet/Worktop Protector". Supposedly made from solid granite, ground and polished. Its 14" by 18", 1/2" thick. All for less than a tenner in cost - this seems a bargain! A large ceramic bathroom tile would do just as well.
Engineer's blue is amazing stuff. If you leave the lid off the tin overnight, the gooey blue jelly will be found up the wall and creeping onto the ceiling, never mind on your clothing and lounge furniture. Do take care - a little goes a long way, trust me on this.
The base was shown to be pretty good, but some of the top face pads would need attention - they were all above the required height above the main top surface.
Anyway, I gave the base of the casting a lick over with a two point tipped tool (in place of a flycutter). Very little needed taking off. The "wedge" block clamps I made earlier proved their worth in setting up on the table - dead simple and easy.
(http://i336.photobucket.com/albums/n354/klank_photo/BedMilling1.jpg)
I now had a true surface to place on the milling table/wooden packing beneath and could deal with bringing the pads to the correct height and milling out the flywheel/crank disc slots more neatly.
The back edge of the base was a bit out of true, but the other edges were good to go.
(http://i336.photobucket.com/albums/n354/klank_photo/BedMillimg2.jpg)
Points to remember - using a "tipped" cutter - the aluminium material tends to "weld" itself to the cutting tips as the work proceeds - needs frequent cleaning off to maintain a good finish. You can see a few imperfections due to this. I suspect the same problem will occur with a flycutter?
I then gave the bed a quick spray over of black engine enamel (from an aerosol) ready for marking out the pads for drilling/tapping the mounting holes.
I mounted the bed on a pair of accurate angle blocks with engineer's clamps and set - to with my vernier height gauge so as to get all of the drilling positions as accurate as possible - I could have done it by coordinates on the mill table - but from some little experience, for me this is a recipe for disaster, what with backlash and no DRO's.
I wish I had a DRO height gauge - easy for re-setting to zero. With a vernier one, you must concentrate on what you are doing and "where you are" as you move up and down. A cheapo calculator is of great help.
Note - suitable background music may help here - I am getting very deaf now, so I have equalised all of the music to + 87db. on my mp3 player - played back via an old audio amp/speakers in the workshop. Who am I to deny the delightful sounds of Bob Marley and classic Stones to my neighbours and my household?
(http://i336.photobucket.com/albums/n354/klank_photo/MarkingOutBed.jpg)
Before this, I had spent some time changing all of the given plan dimensions from imperial fractions (as supplied) to metric. Just my choice.
I also photocopied all of the many plan pages so as to keep the originals as pristine, and the copies for annotations/changes and comments plus oily finger prints on the bench.
More to follow.
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Hi Peter
Looks an interesting engine, and you've made a good start, look forward to following your build log.
Stew
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Peter, :wave:
Nice to see you are going to have a build thread. Looks like a nice kit to build and it's good to hear things are in good shape with it.
I see you have marked directions of which way to crank the Z for up and down... :) Is your sense of direction going as well as your hearing??? J/K I had to do the same thing with my feed directions on the lathe..:)
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Hi Peter
Thats looks a very good kit of materials you got yourself there :thumbup: ,, and can see this will be a good thread to follow :med:
I have also noticed you have put your wedge clamps straight to use on holding the base casting :dremel:
Rob
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This was an intressting project, I will be follow you. :thumbup: :thumbup:
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Thank you all for the very kind encouragement guys. I hope this will still be a worthwhile thread in a few week's time.
Stew - I am in awe of your Southworth and the watchmaker skills you and others post with such gay abandon (!! well you know what I mean) - this basic beginners' kit would be a piece of shlock/ easy peasy for all you guys - knocked off in half the time no doubt.
Bob - yup, I am getting deaf as a post but it is not (yet) affecting my sense of direction. Honestly - I use a Botch Li-Fe batteried drill/screwdriver with a simple adaptor in its chuck to push onto the Z axis drive shaft, with a keyway cut out, in place of the handwheel. Acts as a poor man's power drive up and down (that milling head is d**n heavy). I still cannot remember which way the direction control switch should be for "right and left" on the drill - so I give it a quick pull on the trigger each time and match the chuck movement it to the arrows on the base of the mill. Stupid, I know - but very effective - leaves little chance (ha ha) for getting it wrong - mind you, that's not to say I haven't had the odd coming together under power if you know what I mean?.
Best wishes/respects to everyone
Peter
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Have GLR corrected their drawings for the boiler?
they supply stays but they are not on the drawings ( as supplied to me ) nor is the SWP ?
I have the boiler kit under the bench so to speak , when the current big job is done about 4 years in with another 4 to go ( BR class 4 tank in 5 inch gauge )
Stuart
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Stuart,
You've got me worried a bit now.
The boiler plan, as supplied shows no sign of stays - neither do the various abridged plans, nor text in the boiler build handbook - re-publishing Stan Bray's build articles in the ME.
The full plan appears to be that which was published in the 1950's - going on its style/layout.
Absolutely no mention anywhere of stays - and no Phos. Bronze rodding supplied for this in the materials pack.
I (possibly wrongly) assumed that the boiler was rigid enough by virtue of the fire tubes and gauge of materials and by the lack of reference to stays in the literature. - am I in error here?
If so, I will get back to GLR.
Showing my ignorance - you mention "SWP" - what is this?
Regards
Peter
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SWP Safe Working Pressure
It looks like you got the same reprint plans as I have it does not show stays but they supplied them , when the boiler first came out they advertised it as 80 psi then later they advertised it as a 40 psi unit
DAG Brown has modified one with more tube and fire box stays ( 1/8 copper rivets silver soldered in round the fire box area two row 1 inch centres i believe )
its the stress on the fire box inner that the trouble its very close to the yield point after you have made the boiler i.e. fully soft .
So mine will be stayed
As a note I did make all my boilers ( loco ) but they are to heavy now I need wheels myself ) the one for the current build cost 2.3K Squids
you will not need stays vertically as the tubes will do the job just fine its the fire box inner thats the trouble , its better to over build with stays now than which you had
If you look up the 3 1/2 boiler build by swhart you will find a good guide
http://madmodder.net/index.php?topic=2998.0
Stuart
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Thank you Stuart.
SWP - d'oh - sorry to be so stupid.
The build handbook for the boiler by Stan Bray, mentions :- "Suggest the safety valve adjusted to 40p.s.i. and see how it goes (???!!!). (Quote):- "The nominal working pressure for this boiler is 80psi but its initial test should be to 160psi."
Well that's helpful isn't it!!
In view of those sort of pressures, I would have thought that stays are a MUST - you are absolutely right!.
I shall contact GLR tomorrow about this.
Thanks kindly for the link.
I used to watch the class 4's in and out of Waterloo on empty stock etc. A very handsome design (? Riddles' reverse engineered original Stanier design?) - best wishes for its completion.
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Hi Stuart
Just to clear up the issue of staying the firebox end of the boiler - I today spoke with GLR about it.
GLR put me in touch with Peter Smith - he does all of the GLR boiler building, flangeing and fittings fabrication for those customers who wish to purchase the Tina boiler as a ready made item. He has built over 60 of them!
He has edited/ added more up to date comments to the text originally contained in Stan Bray's article - these are shown in the current boiler build handbook as now supplied.
He admits that the main plan supplied is that of the original mE 1950's boiler - which is somewhat out of date with current regulations.
Anyway, as regards the need for stays, in all of the boilers he has built for GLR, no additional stays in the firebox have ever been fitted. He agrees that the fire tubes act as stays in the vertical plane but as the water space between the firebox and bottom of the barrel is so small, stays are not warranted.
The boilers he has built have been tested to 250psi in hydraulic testing and steamed to 160 psi. with no problems.
Although the "normal" working pressure suggested is 80psi, for "Tina" and similar slow revving engines, 40psi would be the normal maximum working pressure suggested.
Interestingly, the weight blanced safety valve shown on the plan is now deemed "illegal" under current regulations and must not be used - although a dummy one could be fabricated. A "pop" safety valve is the correct way to go!
I hope this explains the situation from GLR's perspective.
Obviously there is nothing to stop one adding extra rivets in the firebox - as you say - for peace of mind, but they are not essential.
Peter
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Thanks for the info Peter
at least your mind is now at rest on the subject , But I wish that GLR would bring the plans up to date and get rid of that safety valve
I am still in a quandary as to why they supplied the material for the stay in my kit , although I will fit them when I get round to the build
May I ask you a favour As I have purchased the kit from GLR can I trouble you for a scan of Peter Smiths upto date comments email is in profile
Stuart
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Stuart - no problem I've got your pm and info will be sent shortly.
Peter
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Hi Peter, from the looks of the kit, you've got a very nice build ahead of you. The quality of the castings and the company show through, even in just photos, and I particularly like the look of bronze in engines of all sorts, but particularly in steam engines. I am very slowly working on a back burner steam engine, Ajax, from Tiny Power, and will be following this build very closely, as I expect there will be some to learn from it, particularly from the boiler part, as I plan to build one out of an old ET Westbury book, but have never built one before. Very nice start, and the discussion regarding the boiler is very informative, particularly the answers back from the company, with real numbers as to their own pressure testing standard. :beer: Cheers, Jack
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Thanks Peter for the amended notes
Although I would take their boiler maker to task with his 250 psi hydro test when the boiler is specced up to be tested at 160 psi WP of 80 psi , to me that is placing unnecessary stress on the boiler and is not needed. thats 90 psi above the design calculations
But as he is a boiler maker I will leave it at that
Stuart
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Thanks Jack and Stuart.
Good to hear from you.
The big question for me (at a later date) is whether to opt for coal firing or lpg/ceramic burner.
Obviously, the gas firing is simpler, cleaner, much more easy to control (steaming rate and so on) and heat is instantly available.
Coal means a properly fabricated door/ring, a blower, a grate (materials for that are extra), and a much messier and harder to control affaire all round!
BUT - the attraction of the latter - if you are a masochist - is the correct SMELL/ATMOSPHERE, and the chance to make a scale sized shovel etc.
Plus the challenge of the extra fabrication work - maybe make the grate, fire-hole/door etc. anyway and use a gas burner as an option (the fire box sits over the grate) - just swap them over - assuming there is enough gap for gas/air combustion - lots to consider - but I do fancy wielding a shovel and pricker (in miniature).
I'll get some more work done tomorrow on the bed plate and maybe start the flywheel, and maybe post it - today was a non starter - domestic duties call.
Best wishes and respects
Peter
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I marked out the drilling points on the various pads as per the supplied plan.
I am not too happy about one of them and the adjacent hole for the crank disc - seems slightly out of place according to the supplied dimensions!
It may be prudent, therefore, to leave centre popping/drilling/tapping until later - until the various engine elements are ready for mounting - and see whether more serious attention is needed to the bed.
(http://i336.photobucket.com/albums/n354/klank_photo/Bedmarkedout.jpg)
Flywheel next.
This is how it came in the kit - virtually no flah at all and pretty true, apart from tapering to the wheel thickness at its rim. The bosses were of unequal length, but well within the required dimensional limits and both appeared true to the outside diameter following some quick and dirty work with calipers/ruler.
I was particularly impressed with the condition of the spokes/inner wheel rim - very little to do here.
All in all - a very nice casting.
(http://i336.photobucket.com/albums/n354/klank_photo/Flywheelcasting.jpg)
In Stan Bray's build, he recommends setting up the wheel immediately in the 4 jaw, and tapping it into position using a scribe block/chalk to get it in the ball park.
Given the overall look and trueness of my casting, I decided to go another way, and find the best centre on the longer boss face first.
I licked it over with a file and then scribed a series of diameters with a centre finder, having "blued" the boss face with felt tip pen.
(http://i336.photobucket.com/albums/n354/klank_photo/Centrefind.jpg)
The centre of the cluster of lines, where they crossed was popped. Sorry - a poor photo - not all of the scribed lines show up too well but there was very little divergeance where they all crossed.
(Note - I know all of this is pretty basic for many of you readers, but this somewhat elementary stuff info may be of use to newbs - as a "beginners' engine". No offence meant to anyone who reads this!)
(http://i336.photobucket.com/albums/n354/klank_photo/centremark.jpg)
I set up the casting in my 5" 4 jaw - plenty of meat to grip with the jaws reversed.
Using a tailstock centre, and home made wobble bar in the popped mark and a clock, it did not take long to get the casting rotating true around the mark.
(Big apologies - I did not remove my tool post before taking the next two shots - I was in a bit of a hurry, and not thinking "ahaead").
(http://i336.photobucket.com/albums/n354/klank_photo/centrein4jaw.jpg)
I then used a scribe/block to see whether the inner wheel rim/spokes were running true(ish) in the facing plane.
What a blessing - it ran virtually true with no more tapping around or wedging out the rim.
Even better there were no knobblies/inclusions around the inner rim or where the spokes joined.
All in all, an extremely nice casting by the looks of it.
(http://i336.photobucket.com/albums/n354/klank_photo/rimcheckin4jaw.jpg)
I used a cheapo brazed/tipped set of tools to start the machining - They are a bit clunky (well they are REALLY CHEAP) but withstand all kinds of abuse and work very well on cast iron.
At this stage, I just worked on the outer rim/face/spokes and boss - brought them to near finished size.
(http://i336.photobucket.com/albums/n354/klank_photo/awautingboring.jpg)
Next up - to bore the centre hole and finish the other side.
The plans show a grub screw fitting for the flywheel on the crankshaft - not ideal. A flywheel should always run perfectly true and I don't like the idea of a grub screw - it might cant the wheel ever so slightly on its crankshaft when tightened, and it can be a weak means of fixing.
I would consider a "coned brass sleeve/set screws and jacking screws" set up normally for an outside flywheel but as this one sits inside the bearings and space is tight, as Stan Bray says, I shall use a slotting tool on the finished bore to make a small keyway fixing.
I shall turn up a stub mandrel for mounting the casting after boring/slotting to do the finishing and outer wheel rim face.
I hope to post a bit more tomorrow.
My sincere thanks to those who posted such encouraging and kind comments.
Best wishes
Peter
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Nice work I am looking forward for the next chapter :thumbup:
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Hi Peter :thumbup:
All good stuff showing your method of work :med: ,,,,,,,,,,,,, looking good :clap: :clap: :clap:
Rob
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Benni, Rob - thanks.
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Peter, I've always liked the look of those GLR engines. Will be nice to watch this come together, a proper working steam plant. :thumbup:
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Thank you Nick.
Work in the shop today was somewhat interrupted - s.w.m.b.o. insisted I watched "The Wedding". To be fair, what a joyous day for so many people. Worth watching and wish the couple well.
TIP
Going slightly off topic here, I use the 4 way tool post as supplied with the lathe for the cheapo brazed tip tools - they fit perfectly to exact height.
For most other work, I use a poor man's quick change toolpost (one day I will get a "proper" one - but this does o.k.).
Due to its design (the tool holder hangs over one side away from the tool post itself), the pressure on the tool in the holder, tends to impart a bit of extra "twist" to the tool/ holder, around the post, unless the handle is really done up tight.
I have not seen this tip posted, so will give it here :- for two or three squid, Arc. Euro sell needle roller races, with a pair of thrust washers (top and bottom) to help correct this situation.
I have found fitting one of these sets a real bonus - the cheapo q.c.t.p. now sits exactly where I want it without straining the guts out of the handle. It also works just as well on the 4 way.
A very well worth investment for such a tiny outlay.
I had better add - I have no connection at all with Arc. Euro, except to say they are a very friendly and most helpful firm to deal with.
I have tried to show the race, minus top washer here :-
(http://i336.photobucket.com/albums/n354/klank_photo/Needleroller.jpg)
And in use, here :-
(http://i336.photobucket.com/albums/n354/klank_photo/ontoolpost.jpg)
Now, back to the Flywheel.
Rather than just drill'n'ream, I decided to follow Stan Bray's advice and bore the hole first, just in case the drill goes walkabout.
I centre drilled the hub and ran a pilot drill 9/32" dia through.
This is a tad over the dia. of my smallest boring bar (1/4" dia).
With the boring bar tool tip on centre it is then a case of taking small cuts through the bore to bring it to a tiny bit less than the crankshaft dia. (1/2").
(http://i336.photobucket.com/albums/n354/klank_photo/boringflywheel.jpg)
Going off topic slightly, there was a most excellent thread recently (I cannot find it right now) on making a "Y axis" read out for a lathe using a long travel dial gauge. (For us lesser citizens who cannot afford DRO set ups - here's wishing!)
Sourceing a long travel plunger dial gauge, without paying through the nose for it was difficult, but once again, Arc Euro came to the rescue. They do one at quite a modest price compaired to flea bay etc.
I now use this set up for really "important" stuff - I find it much more reassuring to see the dial clock hand move with confidence it is right, rather than try to remember the handwheel collar numbers. (I get too confused at the wrong moment using handwheel collars - let alone making sure backlash is dialled out!).
Anyway, for this operation, I set it up for the boring work.
(http://i336.photobucket.com/albums/n354/klank_photo/dialgauge.jpg)
Now its just a question of following through with a 1/2" reamer at slowest possible revs. (The crankshaft is 1/2" dia).
(http://i336.photobucket.com/albums/n354/klank_photo/reaming.jpg)
With heart in mouth (cos there aint no going back), I took the flywheel out of the 4 jaw not forgetting to write down all of the appropriate dimensions I have got to. Essential to make the other side a "mirror" of what has been done. Its very difficult to try and measure rim thickness or some such, on the side facing the chuck if you don't - yes I have done that too often.
I then re fitted the flywheel to the 4 jaw with the other untouched side outmost, using a soft faced mallet to get the finished rim hard up against the inside faces of the 4 jaw. A quick look with the lathe running will tell if the machined face is running true - fortunately, mine was.
You don't have to get it dead centred as all to be done now is face the outside of the boss/hub, and bring it to length.
I then turned up a stub mandrel from a length of 20mm mild steel bar. Allow sufficient to hold in your 3 jaw - or I used a collet.
Once this operation is started, the mandrel must NOT be moved form its location - make sure it is held in TIGHT!
All to do with keeping everything concentric at this setting. (Trying to avoid a wobbly flywheel).
Turn down sufficient length, slightly less than the thickness of the flywheel to exactly 1/2" dia. - the thickness of the crankshaft - or better still, keep offering up the flywheel as the turning down proceeds. You need a very good, slop free fit. Leave a good accurate shoulder inboard.
I turned down the end, allowing for the thickness of the flywheel, plus a bit, to 10mm dia, and I threaded this M10 using a tail stock die holder.
The flywheel can now be gripped with a washer and pair of nuts on the mandrel, leaving all of the untouched face plus the rim to be machined without further re-setting.
Here's the stub mandrel.
(http://i336.photobucket.com/albums/n354/klank_photo/stubmandrel.jpg)
Just an observation, machining cast iron without suds/coolant makes the casting extremely HOT!!
I suppose coolant/suds could be used, but the clearing up afterwards is disgustingly messy - thick black gooey sloppy muck everywhere. (Done it once - not again unless I have to).
I am very conscious that all of this is very basic to many, but as I said earlier, I am trying to write this for a beginner.
If anything is wrong or dangerous - please shout, 'cos I am learning too - but be kind!
Best wishes,
Peter
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Good work :thumbup: :thumbup:
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Well shown Peter :clap: :clap: :clap:
Stew
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Thanks Benni and Stew.
I'll try and keep going tomorrow.
Did anyone notice my first (deliberate - ha ha) mistake?
I could have, maybe should have, cut the slot for the flywheel keyway fixing, after boring/reaming, whilst still set up true in the 4 jaw.
Oh well, I shall attend to that later.
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Not a lot done today.
I finished machining the flywheel and spent an hour or so on the bench with some filing and a little application of miniature sanding drums on my Dremel to finish the spokes, and triangular spaces between them.
It seems logical to make the crankshaft and main bearings next, so now is the time for slotting the bore of the flywheel (which I should have done earlier), since that part of the crankshaft going through the bore will also be slotted for a keyway to match.
I re-mounted the flywheel in the 4 jaw, using a piece of 1/2" bar in the tailstock drill chuck to get it in the ball park between the jaws, then using packing to protect the rim, set it to run true on the shaft with a clock.
Some time ago, I made a cross slide mounted slotting fixture from a casting (College Engineering). It is pretty meaty, but different diameter end bars can be mounted to the piston.
This is the set up (the slotter handle is pulled clear) :-
(http://i336.photobucket.com/albums/n354/klank_photo/Setupforslotting.jpg)
Here is the "business end" :-
(http://i336.photobucket.com/albums/n354/klank_photo/Slottingtooltip.jpg)
And the finished (slotted) flywheel.
(http://i336.photobucket.com/albums/n354/klank_photo/FinishedFlywheel.jpg)
The crankshaft next.
It is not a "built up" one - rather it is a straight shaft with a "fat bit" in the middle to carry the flywheel, and a crank disc secured at the outboard end. This too will be slotted/keyed to allow easier dis-assembly.
More anon, but thanks for all of the kind comments.
Peter
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Again very nice build :clap: :clap: :thumbup:
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Very nice build so far. I am making just the boiler its almost ready to be silver solder together. looking forward to the seeing more of the engine.
William
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looks great Peter keep up the good work !
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Benni, Bob - thank you for the encouragement.
William - did you make your own flanges etc.?
If so, what material did you use? That is something I am going to have to think about.
How did the tube plates go?
I am very interested in how you get on with the build.
Best wishes
Peter
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Peter
Just had a look at starting the boiler build ( I need to test some scale injectors ) If you have the same drawing as I do check out the specs for the bushes mine say brass ( bad ) but the supply bronze ( under size ) the ones for the top connectors do not thread match connector is 26 tip bush is 32 tip
the drawings also do not show enough bushes as to the layout
the drawings do not show the bush for the feed water clack ( should be two ) one for a hand pump and one for another means ( injector 1/2 pint per min should do ) my loco should only need 12 oz per min but that has two injectors )
What I am trying to say please look at your drawings and satisfy yourself that you have it firmly in your mine before you drill a hole in the shell ( note put an extra bush in round the back ,you can fit plug in it , you never know when you may need it )
good luck with the boiler build , your engine build look like it is coming along nicely , although I think you where near the limit on that chuck for the flywheel with the jaws out that far you run the risk of damage to the scroll and the jaws ( just a point for you to think on )
As I said I will be staying my fire box tube , for peace of mind on my part , but hey that me :D two belts and braces :)
I am assuming that you have not done a boiler before but common practice is to feed the hand pump low down in the water space and the injector into the steam space , I will be step soldering the bushes into the outer tube as well as the fire hole to fire box tube to assist with the later work ( start with 700 deg c silver solder and complete the rest with 610 deg c stuff ) so you do not melt off the first things you stick on use tenacity 5 for the high temp stuff and normal for the rest although you can use T5 for the lot ( recommended by Bogs ) dump the COLD boiler bits into citric acid pickle to clean up
Stuart
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Stuart
Thank you very much for all of the practical advice and advisory suggestions - especially about an extra bush.
I have scratch - built one boiler before - a Tubal Cain design of a small "Smithy's/Babcock" horizontal boiler with underslung water tubes. Ceramic gas burner fired - I added a a "steam drier" in the heating space. All proper in copper with bronze bushes and stay. TC called it "Wenceslas". It powers a small stuart 10H. I posted a build thread on it in July (ish) 2009. I used "step soldering" on that and the clack was fitted down low as you say - fed from a simple hand pump. I made the "pop" safety valve from TC's design - blows off at 25psi, although the boiler was hydraulic tested to 100psi.
Thinking ahead, I shall be swapping most of the fittings over from Wenceslas to the Tina boiler as I cannot afford to buy another set at this stage but that's not for a little while yet. The extra bush could be used for the hand-pump (swapped from Wenceslas) in addition to the feed from the eccentric driven pump on Tina. Maybe another extra bush would be a good idea?
I am thinking also of fitting a "steam drier" coil in the smoke box space - seen it in a thread posted on the RC Forum web site.
There was certainly a goodly length of Phos. Bronze in the kit of materials provided for bushing - but I have not checked its dimensions yet. I imagine that today, model engineer's suppliers have to provide metric sizes as I have been told that now, in the U.K., imperial sized non ferrous stock is getting very hard to find from sources.
Best wishes
Peter
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I am sorry if I miss understood you your post regarding the flanging made me think that you had not done any yet
as to the PB supplied is .532 inches and the drawing ask for two bushes at .564 ( 9/16)
anyway hope you have a leak free build :D
Stuart
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Stuart - I appreciate your kind help and advice.
Next up in the build is the crankshaft - or I suppose crank "axle".
A goodly length of 1/2" mild steel bar is supplied in the kit of materials.
Stan Bray recommends turning it up between centres - "old school". It is turned down each side of the 1/2" central portion, carrying the flywheel.
Here's my set up, starting on one side.
(http://i336.photobucket.com/albums/n354/klank_photo/betweencentres.jpg)
After bringing the bar to size/length, both the centre portion and the outboard end to carry the crank disc were slotted for the keys to hold the flywheel and crank disc.
Here is the axle on the flywheel :-
(http://i336.photobucket.com/albums/n354/klank_photo/crankaxle-flywheel.jpg)
The crank disc, carrying the crank pin is very plain, and to my eye, looks a bit naff compared to the rest of this quite nice looking engine.
Stan Bray machined a rim around the periphery of the disc to give it some texture. Even so, in the photograph of that, shown in the ME, the disc still looks a bit odd.
There is a substantial boss on the inboard side of the disc, so cutting holes or spokes in the disc is not really feasable.
I decided to see what a "pie slice" crank web might look like, in place of the disc and drew one out full size (roughly!!).
The shading may represent a bit of fluting to add a bit more interest. :-
(http://i336.photobucket.com/albums/n354/klank_photo/papertemplate.jpg)
The disc, proper, is machined from a slice of solid 2" dia. mild steel - a generous length of this being supplied in the kit of materials. Plenty of meat to hold in the three jaw, with jaws reversed :-
(http://i336.photobucket.com/albums/n354/klank_photo/Discblank.jpg)
It is a straightforward machining job then, to bring it to size and drill/bore/ream the hole for the axle.
This was subsequently slotted for the key to hold the disc on the end of the axle. Both outboard ends of the keyways in the disc and flywheel were carried around into the ends of their bosses so as to take the head ends of the keys (yet to be made).
The hole for the crank pin was drilled/reamed on the mill table using coordinates to get the required 1/2" off-set.
To satisfy my curiosity, I assembled the flywheel/axle/crank disc (no keys yet) and stuck the paper template on the end of the disc, to get an idea of what it might look like if I decided to butcher the disc.
(http://i336.photobucket.com/albums/n354/klank_photo/Templateondisc.jpg)
I think I'll sleep on this for tonight and maybe attack the disc tomorrow?
Best wishes to all
Peter
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Good work. :clap: :clap:
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You're right about that disc, Peter. Looking at the photo in your first post, it looks a bit utilitarian - more suited to a toy than a model. It shouldn't be too difficult to come up with something more interesting; maybe a crank arm with a counterweight to "balance" the big end would look a bit more interesting?
Andy
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Hi Peter
what about this sort of shape for the disc (http://www.nam-engineering.com/cm/albums/userpics/10002/normal_Part1%7E1.JPG)
Just a thought
Rob
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Rob, you've drawn just what I was ineffectively trying to describe!
Andy
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Having just joined the group allow me to introduce myself. My name is Pete Smith and I write as the proverbial horses mouth as I am the poor soul who makes these boilers for GLR and the count is over 40 complete boilers and hundreds of flange plates so I think that I know a thing or two. I cannot write everything is one session so will treat you to a number of episodes over a period of the next few weeks covering the comments made earlier by previous members. If there is anything you need to know then tell me and I will sort your problems.
The next section is the preface that you will find in the 'words and music' supplied by GLR with the boiler kits. See his website for the various kits available.
The drawings for the mill engine vertical boiler were first published in 1950s. The construction series was written by Stan Bray and appeared in the Model Engineer from March 1997. Since first publication there have been various changes to the boiler codes with reference to construction and testing. Builders may also find that copper sheet has been provided in Metric thickness instead of imperial. This makes no difference whatsoever.
It used to be accepted practice to drill and tap the boiler shell to allow for the fitting of the firehole door and other items. This only allows about 2 or 3 threads in the soft copper and although is was possible to initially fit and make steamtight removal usually stripped the threads. This is no longer accepted practice and ALL screwed fittings to a boiler MUST be made using gunmetal or bronze bushes silver soldered in place. On NO account use brass. This gives you a safe fixing with many more threads and they can be made blind ( not drilled / tapped through ) so that even if the screw is removed no steam will emit.
The weighted safety valve shown in the drawings should be replaced by a spring loaded version safer and tamperproof. It is shown for historical reasons. Irresponsible workers used to add weights to increase boiler pressure with the expected results plus an explosion as an extra.
Ready flanged plates are available from GLR formed to shape and correctly spot drilled only needing to be skimmed in the lathe to fit as detailed in the series.
The boiler may be fired by gas or coal. The use of methylated spirit burners these days is frowned upon by the safety people as it burns with a clear flame and is uncontrollable and easily spilt. The solid pellets for use in Mamod type engines can be used but can be expensive and leave a nasty residue.
Over the last few years there has become available excellent ceramic burners and control valves to fit disposable gas canisters and other cylinders. Clean, efficient and safe, especially where the children are around.
Should you decide to go for gas then there is no need for the firehole, blower or grate as the burner is designed to fit inside the boiler with a flexible pipe to a remote gas supply passing through one of the 3 slots. The air for combustion comes from underneath. This does save a great deal of work and simplifies construction. You can of course make a false door and fit to the cladding afterwards to maintain the appearance.
For those of you who prefer the smell of steam and intend to use coal then the construction of the firehole ring, creating the curve and perhaps the oval and still get a good fit can be problematic and does little for your confidence. There is an easier way. Instead of using the copper ring supplied use a suitable length of 1 1/8th diameter by 16 gauge thick walled copper tube. The hole is made to the tube diameter by any suitable means. Do not use a hole saw of the same diameter as they always cut oversize. It does not matter how much sticks out on the fire side and it can be left square. Using a triangular file make a few nicks in the hole to allow full penetration of the silver solder. When assembling, file the tube end to allow it to fit. Again use the triangular file, assemble with the foundation ring and final soldering to secure. If your hole is slightly oversize then the tube should be annealed and the ends expanded to fill the gap, The outside can be finished afterwards. This will not affect the strength of the boiler but certainly allows easier construction.
If you use blind bushes to hold the firehole door in place consider how to get the holes to line up. They are radial to the boiler. I suggest cladding that part of the boiler on a temporary basis, placing the door in position and transferring the holes through the cladding just to mark the boiler. They can then be drilled and the blind bushes soldered into place at the same time as the ring is secured. Perfect line up afterwards.
There is another clever little way lateral thinking. Make the firebox door in the usual way but silver solder onto it a length of steel tube approx 1 diameter which is a push fit into the hole. The curved shape will align the door and it can be secured with small woodscrews. Much easier.
A few moments to consider the fine stationary engine you have just built. In real life such engines rotated at 30 to 100rpm. The bearings and those on your model are designed for slow speed. Running with the motion and flywheel a blur may be exhilarating but you will soon be facing a rebuild!!!! Most of these engines will tick over at a realistic speed on 20 plus psi.
I suggest setting the safety valve to 40 psi and see how it goes. The nominal working pressure for this boiler is 80 psi but its initial test should be to 160 psi.
When testing your boiler do remove the gauge glasses and plug the holes as they may fail at test pressures. If you live in a hard water area look in your kettle then the small area between the firebox and barrel will soon get clogged with scale. Visit your local chemist and get some citric acid crystals used for cooking mix up a warm solution and fill the boiler. It will bubble away merrily converting the chalk to carbon dioxide. Flush out thoroughly afterwards. Happy steaming.
The next exiting episode will cover stays, boiler testing and fittings.
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Andy, Rob, Benni - thanks again for encoragement - and suggestions.
Peter - thanks for taking the time and trouble to write.
Rob, the superb (is it a cad rendering?) sketch is what I too was thinking of at first - but got sidetracked into picturing "locomotive driving wheel centres - with fluting".
Originally I had a mental picture of a "nodding donkey" kind of pump crankshaft with counterbalance weights.
Tomorrow, I'll try and draw it long hand - (I am not clever enough to use a cad programme!!) and stick it on the disc. I like your rendition - it "feels" right - and looks quite simple to make from chopping up the disc.
Well, now we've got chapter and verse straight from the horses mouth on the boiler - thanks Peter. Looking forward to your next bulletin.
I was afraid the Copyright Police might object if I posted what is written in the up-dated GLR boiler build handbook - it does put things in a better perspective with regards to current good practice and regulation.
Best wishes
Peter
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Is there more than just a passing resemblance between Tina and the "Suum Cuique" engine by Stan Bray, the construction of which was shown in "The Best of Model Engineer Vol 1" which I bought from the local newsagent 18 months ago?
Andy
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Andy - good point.
Insofar as the BASIC DESIGN goes (not the scrap/surplus materials/methodology) - I think there is a lot of similarity between the two - although the Latin one is very much smaller than Tina. Presumably this was deliberate so it could be built using the smallest of lathes. Interestingly - cyl. bore/stroke/flywheel dia. etc. are all just about exactly 1/2 Tina sized - ?coincidence?
Tina does have the advantage of an eccentric driven pump.
As someone said - "I suppose there are only so many ways to design a mouse trap"?
Peter
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loco
Peter
:offtopic:
thanks for the write up look forward to you further instalments
my problems started when GLR did not supply any documentation with my kit , they then supplied a set of drawings that show the bushes in brass with some shown with the wrong threads to match the top connectors.
nor do they state the SWP or test test Pressure ? (which I believe is illegal for a pressure vessel )
I did not get any documentation ( reprint form Stan Bray )
In my kit was supplied 18 1/8 x 1 inch copper rivets that is what lead me to calculate the stress on the fire box wall in a fully annealed state and concluded that it could yield at a TP of 160 for a 80 psi SWP during the interim period I noted that the WP on there site had dropped to 40 psi
These are my opinions and are based on my findings and the kit that I was supplied with, which still has note been completed my last build was for "doris" but the boiler for my class 4 tank 5 inch G was farmed out to big for me to handle from a wheel chair :)
Stuart
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Hi Peter
I bought the kit with the flanged plates, but i am building a larger boiler and have used MDF formers to flange the plates (end plates are in 2.5mm copper) they last long enough to shape the copper providing you keep annealing the copper. I have been working on the boiler for a 18 months on and off, i don't have any photos of the work. I just need to drill the holes in the barrel and form the foundation ring. I will try and put some photos on my thread, i and hoping to get back on the build after taking time out to get married. The fly wheel is looking good, Tina is a nice engine but i have enough projects........
William
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Thanks William - very best wishes for your wedding.
Peter
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getting married , watching the royal wedding whats the whorl of ME coming to :doh:
only joking our wedding was in 1968 :)
Peter ( Klank )
just to let you know I have cleared the bench for this little boiler build , just done the foundation ring what a job, got the outside fitted then inner would not go in ( metric / inch materials me thinks ) so a delicate job to skin out the inside for a slightly loos fit got to leave a little room for the SS
Should be done by the end of the week if we get a dull day to do the soldering ( have to do it outside the WS is to small for big burners inside ) I cannot see the colour ( color for across the pond ) of the metal in the sunshine
I will alert you if I run into any big loo loos
then its time to make all the fittings WG etc
Stuart
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Hi Peter :clap: :clap: :clap: :thumbup:
Looking forward to seeing what you decided to do with the crank , ,, yes that was just a quick example i drew in CAD ,, easier to draw than describe :doh: .
Stuart ,,, i hope you will decide to start a thread on your boiler build :poke: :)
Rob
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Rob
its getting the pic's to the correct size I am beta testing a new OS for the Mac called Lion at the moment coupled with the camera takes a 21 - 50 meg file they are huge but good Qi
Stuart
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Trying to stay on topic :-
I used Rob's very nice CAD type sketch, and set to with a hack-saw and file on the plain-Jane crank disc having used a paper template.
I am quite pleased with the result, and in a fit of "creativity" turned up the crank pin and keys.
Here are the components :-
(http://i336.photobucket.com/albums/n354/klank_photo/Flywheelcomponents-1.jpg)
Here it is assembled :-
(http://i336.photobucket.com/albums/n354/klank_photo/assembledflywheelshaftdisc.jpg)
One glaring error shows here - the "reveal" in the crank disc for the head of the key locking it to the shaft looks dreadful. Its too big and badly spotted. (I did say this was a "warts and all" diary).
I have subsequently mixed up a blob of Stabilit Express (good quality epoxy) with some iron filing dust, and back filled that orifice and re - cut it to a better fit. After sanding/polishing/painting it shouldn't look too bad - I hope!
Next up is the connecting rod.
According to the basic plan, a goodly length of 3/4" X 1/4" mild dteel bar (flat) is supplied. The basic con. rod is just this, drilled/reamed at each end for push - in brass or bronze bearings. To say it will look a bit naff is a kindness - but it is very simple - this IS a beginners' engine. In real practice, a straight bar rod was never used.
Stan Bray suggests using the supplied material as a basis for something better.
He turns the bar up to a round(ish) cross section having drilled/reamed the flat ends, turning a slight taper up to the centre of the rod, leaving two flat ended big/small ends. These are given a bit more dignity with "dummy" bolt heads and scribing across the centre to look like proper split - end bearing caps.
He also suggests another alternative would be to leave the rod as flat, with dummy ends, but with a "fish belly" double taper down top and bottom edges - plus a bit of fluting if you are so inclined.
I am including a couple of pics. of this type of con. rod which I made for a "double side rod" engine - although these rods have "proper" wedged marine type small ends and split big ends. (That engine is not yet finished - lots of plumbing and governor to do yet). :-
(http://i336.photobucket.com/albums/n354/klank_photo/Siderodengine.jpg)
and I tried to get a closer view of the fish belly rod here - not very good :-
(http://i336.photobucket.com/albums/n354/klank_photo/Siderodsdetail.jpg)
For this build (Tina), I think I'll go the Bray way and turn the rod round(ish) section and tapered. To fit a split big end is quite feasable, but I shall take the "easy" option and try and dummy it.
The marine/wedged small ends, each held by a strap on the double side-rod engine was a bit of a bother - not to be willingly repeated - especially as Tina is about 1/3rd. smaller - the job wouldbe really fiddly.
I shall post more later - got "family stuff" to take care of first.
Best wishes, and thanks for the encouragement
Peter
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Comming along nicely Peter.
Thats also a good looking engine was it made from castings ?.
Stew
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Hi Strw
Yup - made from a kit of castings eventually furnished by a certain vendor (located up your way) after all kinds of trials and tribulation.
I just put the photos up to show a fish belly type of con. rod.
If you like draw - filing, its a good exercise - the trouble was getting two of them to look identical!
For Tina, one is no real problem.
Peter
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Hi Peter
Crank disc and other parts turned out spot on :clap: :clap: :clap: :clap: ,,,,,,,,, :thumbup:
Rob
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Now for the next exiting episode!!!
STAYS These are only needed on FLAT sections of a boiler to prevent the sides bowing out under pressure. Consider a loco boiler. It basically comprises a cylinder fixed to a square or rectangular box. The cylinder is self supporting whilst the box is not. At the front end of the boiler is a flat plate ( smokebox tube plate ) . This is stayed to the throatplate in the firebox by means of the tubes and is usually stayed to the backplate or backhead by means of longitudinal stays, 1 often being hollow and used for the blower. Remaining stays will be solid. They should be threaded, blind nutted and silversoldered. However, opinion varies as to the real use of these longitudinal stays for after silver soldering such stays are observed to have sagged so much in the middle that their efficiency is doubtful.
The top or crown of the firebox is usually stayed to support itself the shape being round or rod stay, or of the girder type, these being usually riveted and silver soldered.
The firebox stays are the most important. There size and spacing should be chosen with care. They are there to support the unsupported sides which are not self supporting - got it??? The boiler designer will have done the calculations for the spacing.
This boiler is basically a self supporting structure. It needs no side stays and the tubes serve the purpose of longitudinal stays.
Fancy an experiment?? Find a square plastic bottle and a round one. Holding carefully half way up, blow into it and feel the sides expanding - or not. Notice how the manufacturer has added corrugations to make it more rigid. Think about the pressure inside - does it go fizz when opened?
Next time boiler regs and testing.
Pete
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Now for the next exiting episode!!!
This applies to the UK and those of you across the pond will have your own regs.
ALL new boilers need to be proved or tested. Would you buy a gun that had not had the barrel proof fired at twice the normal velocity? The initial hydraulic test is at 2X working pressure and such a test is valid for 4 years before the steam test. This allows s-l-o-w builders to complete. The holes are all plugged and NO boiler fitting should be on the boiler. Having passed, all the fittings are installed, piped up etc ready for a steam test at normal working pressure during which time the safety valve should be set and the pressure gauge red lined. A pass means the boiler is valid for 1 year. Subsequent hydraulic test shall be at 1.5 times working pressure annually followed by a steam test. This applies to all boilers over a capacity of 3bar/litres. The GLR boiler running at 80 psi just exceeds that level and requires CE marking if made commercially but is down rated to 40psi so it does not. If you are making it the 80psi is fine.
The kit of bits says 80 psi whilst a completed ready to run boiler is rated at 40 psi.
However every boiler I make is tested to 160psi hydraulically.
In a former life I was a teacher of engineering, metalwork and woodwork. About 20 plus years ago a lad built one of these boilers. After much soldering and resoldering and resoldering the boiler was finished and held 160psi.After he left and did not want the boiler my technician decided a destructive test should be carried out. He made suitable plugs, secured with Boss white ( no PTFE in those days ), and after fixing it to a bench outside on the field and with the plugs facing the opposite way all was ready. Being the man he was, readings were taken to see how much the barrel would bulge as the pressure increased. At 50 psi intervals we stopped and made measurements. The gauge only went up to 250 psi so we stopped. The increase was only a few thou. No bangs, creaks or groans. DO NOT DO THIS TO YOURS. We cut the boiler in half to examine the inside and the tubes were perfect.
Pete
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help
I can build boilers but how do I put a photograph here???
Pete
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help
I can build boilers but how do I put a photograph here???
Pete
This may help Pete
http://madmodder.net/index.php?topic=607.0
Stew
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Trying to get back to the engine build - the con. rod. next.
"Read the manual!"
In the build handbook, there is a chapter at the end - a sort of "addendum" - devoted to another more recent published article - appearing in MEW in 2009 - by Harold Hall.
He is dealing with basic work for a mill and rotary table, and uses some of Tina's castings to illustrate some techniques. Specifically, how to machine a round section/tapered con. rod and how to use a rotab. to finish the small end (rounding it off).
In this article, HH publishes a table of lathe dial movements (after some complex mathematics and other good stuff) for "saddle [X axis] and tool infeed [Y axis] so as to obtain the required tapered shape of the rod for Tina.
Unfortunately, for me, they are for an imperial dial measurement lathe (mine is metric), but it is quite simple to convert them. All of the X axis "slices" are the same, so all in all it is not a difficult job to follow.
HH's finished result looks a lot better than simply "taper turning" with the compound slide off-set - it's a bit fatter in the middle than Stan Bray's original, but still looks good.
This exercise looked far more interesting than a fish belly flat rod - so I discarded that idea.
I decided to set - to and see if I could turn up the same form, starting with a suitable length bar of BMS - 3/4" X 5/8" - which I had in stock. (Not supplied in the kit).
Following HH's notes, the bar is marked out to show where the big and little ends will be, the material in between to be turned away to a round section of the max. dia. of the con rod.
Bar marked out :-
(http://i336.photobucket.com/albums/n354/klank_photo/Startingmaterial.jpg)
The extra length will be turned down to a pair of spigots.
The bar was pop-marked for a centre at each end and put up in the 4 jaw with a tailstock centre and wobbler, to turn true. :-
(http://i336.photobucket.com/albums/n354/klank_photo/setupin4jaw.jpg)
A 1/2" spigot was then turned up to the end mark, and centre drilled. :-
(http://i336.photobucket.com/albums/n354/klank_photo/turnspigot.jpg)
The same procedure then carried out for the other end, and the meat in the middle turned away slowly, holding the bar in a collet and tailstock centre - as per HH's recipe. :-
(http://i336.photobucket.com/albums/n354/klank_photo/turndowncentre.jpg)
Now came the interesting bit, following a table of 26 dual dimensions in X and Y axis to gradually turn away the material on one side of the centre so as to achieve the desired taper.
It wasn't as daunting as I first thought, and doing it slowly with care, the basic shape emerged, working from right to left from the mid point.
It was then necessary to do some filing/wet and dry of various grades to remove the machining marks whilst rotating at the same set up - here is the left hand side virtually done. :-
(http://i336.photobucket.com/albums/n354/klank_photo/oneendreduced.jpg)
The same procedure was then followed working from left to right from the centre, without changing the set up (I don't know why a spigot at the other end is necessary, unless the set up is turned around end for end?) :-
(http://i336.photobucket.com/albums/n354/klank_photo/bothsidesdone.jpg)
The middle is now nicely tapered each way.
This leaves two oversized blocks at each end, plus the spigots.
The latter were sawn off, and a quiet hour spent on the mill to reduce the big/small end blocks to the required thickness and drill/ream the holes for the bronze bushes carrying the crank pin and gudgeon pin. :-
(http://i336.photobucket.com/albums/n354/klank_photo/awaitingendturning.jpg)
Now its a question of rounding off the perimeter of what will be the "small end" - HH recommending setting this up in the rotary table.
I have to confess to being a real novice at using a rotary table - so the possibility of making a bish of what I have got so far alarms me a little. I think I'll have to read up on Rotabs. for Dummys first!
More anon.
Peter
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I could not do a lot today, dentist appoitment interfered - such fun!
I decided to make use of a small home made receiver/adaptor with my rotary table.
This would allow the collet chuck to be fitted to it, thus holding the small end of the con rod on a mandrel, without going to all of the trouble in making "mounting fixtures" as shown HH's article.
After setting up everything to run true, I off-set the table by the appropriate amount and gently milled off the edges of the small end, taking light cuts around and increasing the down feed a bit at a time with an 8mm end mill. Here's the set up about half way through. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Millingsmallend.jpg)
Two bronze bushes were turned up for the two reamed holes.
That bush in the "big end" is meant to be proud on both sides - according to the plan! :-
(http://i336.photobucket.com/albums/n354/klank_photo/Bushedrod.jpg)
I will start on the main bearing castings tomorrow, toothache permitting!!
Peter
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:clap: :clap: :clap: :clap: :clap: :clap: :clap: thats a mighty fine looking con rod Peter :thumbup:
Rob
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Nice work :clap: :clap: :clap:
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Thanks Rob and Benni.
Workshop time was reduced today (had to go shopping with s.w.m.b.o. for her wedding outfit - number 1 son is getting married shortly - quite an experience, trying to be tactful, yet positive, whilst standing on razor blades).
Anyway - I started on the main bearing blocks.
The main bearings are solid gunmetal, split, but contain no separate bearing shells
These come as three castings - two separate "bases" and a pair of "tops", joined together. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Originalmainbearingblockcastings.jpg)
The general quality of the castings was good, apart from the bottom of the bases being canted over somewhat, as can be seen above. Apart from that, they were all reasonably "square and true", although somewhat oversize compared to the plan dimensions.
Minimal dimensions are given - and not really needed - just the bolt hole spacings for both the bottom of the bases and the those holding the two bearing halves together, plus overall thickness and length of the base.
6 BA bolts are recommended to hold the two bearing halves together.
There are several ways to machine these - SB recommends doing them all in the 4 jaw (he did not use a mill at all in his notes), whereas HH recommends using the milling machine/toolmakers' vice.
I went the latter method - quicker set up time.
I have not bothered with mundane photos of doing the basic macining - points to note obviously are to get the centre heights exactly the same for each pair (using a height gauge on a flat plate or whatever), and the vertical faces at right angles to the base and parallel to each other.
Here's one lower bearing half part finished, compared to an untouched casting :-
(http://i336.photobucket.com/albums/n354/klank_photo/Partfinishedbottom.jpg)
I macined the top castings together, before separating them. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Doingthetops.jpg)
I temporarily joined the two halves together for each pair with cyano., not forgetting to mark each pair for re-assembly later.
Each pair was then marked out, drilled tapping size for 6BA (sufficiently deep to accommodate the supplied bolts - nice to have them as part of the kit), separated and the lower halves tapped, the upper halves opened out to 6 BA clearance, and the top faces where the bolt head will go, spot faced for the diameter of the bolt heads.
Each pair of bearings could then be assembled with the bolts..
I know that some may prefer to use soft solder thinly to join the halves together instead of cyano. - just my preference. It does hold quite well.
I chose to do the boring for the crankshaft pin in the 4 jaw, together with final facing and turning up the shoulder around the boss, which has been previously machined away when bringing the blocks to size.
The centre mark for the bore was measured, checked and centre popped.
I used a chuck back stop for this set up, which simplified matters considerably - you can just see it here behind the bearing casting :-
(http://i336.photobucket.com/albums/n354/klank_photo/Setin4Jaw.jpg)
Slight digression here.
There have been many published plans/articles for making a chuck back stop, indeed Bogs has done a very good thread on this.
A friend put me in touch with a link (I cannot find it at present - if anyone else remembers where it is, please add it) for making a truly simple, effective yet elegant backstop requiring minimal components and machining - the picture here shows it far easier than words can explain - its "inventor" should be praised! :-
(http://i336.photobucket.com/albums/n354/klank_photo/BackStop.jpg)
Each bearing block was set up as above, to turn true with a wiggler (wobbler?) and clock.
Centre drill, pilot drill, etc. and your choice to use a small boring bar (recommended) or reamer to finish. (Don't forget to withdraw the back stop a bit first!).
At the same time, the boss face can be skimmed and the shoulder turned back using a left hand tool.
The block was then reversed and put back in the same position in the 4 jaw/backstop, checked to run true and the other boss face/shoulder machining done.
The rest of the casting was then fettled and machined with a small end mill to remove the rest of the rough cast finish.
The tops of the bearing blocks were marked/popped for drilling/tapping the hole for the oil cup - but not finished at this stage.
Here is the result, temporarily placed on the base. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Finished-onbase.jpg)
The overall finish of the bearing blocks needs a bit of fine bench working and elbow grease.
Next up - the cylinder.
Thanks for the support
Best wishes to all
Peter
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You are doing very well, it's a plesure to folow your'e project. :clap: :clap: :thumbup:
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I think you've done a great job there because I don't know what anybody else thinks but those castings for the bearings look pretty awful to me. The fact that you've had to machine them all over makes it kind of pointless, it would have been easier from solid bar. They look great now by the way! :bow:
Nick
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Looks like you sorted them casting well Peter :thumbup:
Stew
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Thanks again guys - you are very kind.
Nick, thanks. Given what you have said about these castings' "quality" and wih great respect and deference to your experience, I feel must have come across some truly shocking castings in the past and treated them as the "norm"!
O.k. my experience is quite limited - I have really only built two and a half engines from castings up to now and compared to what I have been presented with in those, I really thought these weren't that bad - being reasonably "true (ish)" and with no knobbly accretions.
Maybe I have made a mistake in machining all over, but once you start doing shoulders and such, bringing out the "shine" it made the rest of the surfaces look somewhat "rustic?"! So I gave it a shot.
I do appreciate all of your encouragement - compared to the other superb engines currently being built - this is playschool stuff.
Anyway - talking of castings - this is what is provided for the cyl. casting :-
(http://i336.photobucket.com/albums/n354/klank_photo/CylCastingassupplied.jpg)
To me it didn't look too bad, having checked its dimensions with those on the plan, and for "trueness" across the various faces. The only real problem side was the base, where it was partly canted from true to the valve port face - marked in felt tip.
Following SB's suggested method, I decided to start with the port face side of the casting as "datum" and set up for machining the base in my milling vice with the datum side against the fixed jaw, and "squeezy" packing against the cyl. body.
Once done, turned around to lightly machine the port face and check the results with a square.
The casting bore seemed reasonably "linear" throughout, and went ahead and plugged the hole at each end with some turned down wooden dowelling (a length sawn off the end of a garden hoe handle - I expect to get "sanctioned" in due course when my wife finds out!).
After a quick facing swipe across the disc sander, I could then mark out the bore faces for the true centre using a height gauge on my Tesco face plate and popped the centre mark.
I didn't bother with any photos of all of the above as its pretty mundane stuff, but here's the result :-
(http://i336.photobucket.com/albums/n354/klank_photo/Aftermachiningfaces.jpg)
The casting was then set up in a Keats angle plate on the lathe faceplate, using the two finished faces to locate in the larger angle, and some scrap steel packing on the round cyl. body.
It was set to turn true with the usual wiggler from the tailstock and clock :-
(http://i336.photobucket.com/albums/n354/klank_photo/setinKeatsplate.jpg)
Subsequent to this shot, I bolted a counterbalance weight to the face plate opposite the mass of the casting/Keats plate. The lathe would then turn reasonably steadily at about 750 rpm.
After skimming the first face it became apparent that there could be some small casting flaws hidden in the gun metal material. You can just see the "spots" dotted around the face here :-
(http://i336.photobucket.com/albums/n354/klank_photo/signofcastingholes.jpg)
They don't look to be too close to the bore itself and are very small - so I decided to press on.
The boring operation was quite straightforward and I didn't bother with photos of this.
Pilot drill through both bits of wood (there is quite a large central hole in my face plate), then drill out to 1/2" and start boring with a Glanze boring bar with the tip set on centre (it will quickly remove any residual wood from the plug). I used a bore gauge/micrometer to check the bore at various points down its length as it got close to size (1" bore required) and allowed for "spring" in the cuts.
Obviously, a better way of doing this would have been setting up the casting on the cross slide and boring between centres, but my Glanze bar is pretty rigid, and using very light cuts at the end, I am happy with the resut.
I left the bore a tiny fraction undersize, and finished it with some wet/dry paper and paraffin, wrapped around another length of Garden Hoe handle, turned slightly undersize and kept moving in and out as the casting rotated.
I faced the end (removing 1/2 of what I needed to overall to bring the cyl. to finished length) and cut the shoulder, reversed the casting in the Keats plate and did the other face/shoulder.
Following SB's advice, I checked the valve and base faces for squareness to each other and the end faces by bolting the cylinder to the cross slide, and interposing a 123 block between the valve face and the face plate (the latter having been ever so lightly skimmed) and checking for high spots/misalignement. (Sorry, the top slide toolpost spigot is in the way) :-
(http://i336.photobucket.com/albums/n354/klank_photo/setuptochecktrueness.jpg)
There was one slight high spot, and as recommended by SB, I fly cut the two faces ever so lightly from a cutter held in the face plate.
Here is the result :-
(http://i336.photobucket.com/albums/n354/klank_photo/finiishedfirstmachining.jpg)
You can see the casting spots - enlearged here :-
(http://i336.photobucket.com/albums/n354/klank_photo/closeupofcastingspots.jpg)
There do not appear to be any imperfections running through into the bore, and I hope those around the rim side of the end faces will not be a problem, provided a good gasket is used between the end cover/cylinder at this point.
I shall start on the end covers tomorrow (provided I can hide the Garden Hoe again).
Best wishes
Peter
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I have to ask you Keats angle plate what is that??? :zap:
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Benni
A Keats angle plate is a sort of cross between a V block and angle plate.
The "angle plate" part, can mount to the face plate through slots in its flange, but instead of a straight edge across the bottom, it has a deeply machined ninety degree V cut out at ninety degrees to the plane of the face plate.
Another ninety degree V machined plate bolts up to this leaving a sort of adjustable "square" shaped hole as a variable clamp - its pretty well shown in the third photo of this post. The flange and bolts holding the angle plate to the lathe face plate are hidden behind the bigger V and cylinder casting. The lower V plate and its securing bolts are quite clear.
I think Boggy did a write up of how to build one on MM a while ago?
I hope this explains.
Peter
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Nice bit of maching their Peter. :headbang:
Those blow holes are nothing to worry about, they look to be well away from anything inportant.
Benni
This is Bogs write up on the Keats
http://madmodder.net/index.php?topic=1271.0
And this is how I made my own not the best looker in the tool box but it does the job.
http://madmodder.net/index.php?topic=3428.0
Cheers
Strew
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Thats some nice tooling Stew,
Thanks for showing how it should be done!
Peter
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Peter, I was maybe a bit hasty in my judgement sorry if I came across in a bad way and I don't have much experience working with castings, you probably have more. I was just the close up pics of the bearings that got me, I just thought what use is that shape ... then I scrolled down and saw you had machined it all over, which I think looks great but possibly defeats the point of having a casting slightly? I know what you mean by the temptation to make it all shiny though! As you say though, as long as you can get the required dimensions out of them and they are reasonably true / free from blow holes then maybe that's a more important measure of the quality. I see you've found a few on the cylinder but as Stew says, at least those ones won't be affecting anything.
Great work.
Nick
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Hi Nick,
No, not at all did you come across in a "bad" way, nor was it a hasty judgment - I appreciate your views.
The trouble with machining all over is you can never get rid of machining marks in those "hard to reach" areas.
Here's a thought - if the unmachined surface is pretty flat and linear - leave it alone - maybe a lick of paint would serve? (Paint would "take" a lot easier on a "rough" surface than a shiny one).
Thanks for the kind thoughts Nick - a pleasure to read your post
Peter
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Thanks for explaining, there is a lot of diffrent tools and I have just a few :(
I think I have to spend some time to make me some..
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I would just like to add, the Keats angle plates seem to have become unobtainable from our normal suppliers, but if anyone would like to try making one, the castings can be obtained from here
http://www.collegeengineering.co.uk/Castings/558.htm
Bogs
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Thanks for the links Bogs. :thumbup:
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Hi
Keats type angle plates are available from Warco.
Pete
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Peter (Klank)
lathe back stop
http://madmodder.net/index.php?topic=4693.0
BTW boiler done, tested, lagged and test fired ( I did put in some stays as I intend to use it at its design SWP not the derated one ) now to get on and get my scale injector for the class 4 tank tested
cannot post any pic as they are 50 meg after they have been in PS5
Stuart
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I decided to do the piston and its rod next.
A casting in gun metal for the piston is provided (with a nice chucking piece) together with a goodly length of 3/16 stainless steel rod. There is plenty of meat provided.
Here's the casting :-
(http://i336.photobucket.com/albums/n354/klank_photo/pistoncasting.jpg)
The sides of the piston were all reasonably parallel, and after holding the main body in the three jaw, the chucking piece was skimmed down its length until running parallel.
I then held this in a collet for the main machining of the piston body to just oversize finished diameter and length.
It was drilled tapping size through, tapped 3/16 X 40 ME for the rod and counter bored half way through 3/16 for the un threaded part of the rod.
(http://i336.photobucket.com/albums/n354/klank_photo/heldincolletanddrilledandtapped.jpg)
The rod is screw cut 3/16 X 40 ME for half the length of the finished piston whilst held in a collet with as little overhang as possible.
The chucking piece was then carefully sawn off, and the threaded end piston rod screwed on and held with thread lock and left to cure.
The rod with piston attached was then held in a collet, with the piston close to the collet face.
The final machining could then be carried out to bring the diameter to a good fit in the cylinder and length to what was required using very very light cuts with a very sharp tool.
A silicone O ring is supplied for the piston and precise dimensions given for cutting the O ring groove, to allow for a little bit of "roll" in the O ring lengthways in the groove when under power.
This was quite a fiddly operation to get exact, using a combination of a thin "pointy" tool to start, then a very sharp thin bladed parting tool.
The piston/rod should not be moved in the collet until all these operations have been completed (to keep everything concentric to the rod).
Here is the finished piston/rod with the O ring fitted. :-
(http://i336.photobucket.com/albums/n354/klank_photo/finishedpistonandrod.jpg)
Now to start the cylinder end - covers.
These are the castings supplied in the kit.
They are somewhat "coned" but with a reasonable anount of meat to play with.
The inner end cover casting has a rough "spigot" for the stuffing box. :-
(http://i336.photobucket.com/albums/n354/klank_photo/endcovercastings.jpg)
Starting with this one - the inner cover - I firstly held the casting in the three jaw, using my chuck back stop, with the spigot outermost, so this could be lightly machined to get its sides parallel.
The spigot could then be held in the three jaw (with backstop) for turning the main body true (removing the cone) and facing off the outer skin/debris. :-
(http://i336.photobucket.com/albums/n354/klank_photo/in3jawforfirstturning.jpg)
The casting could then be turned around and held in the reversed jaws, plus back stop, to machine the spigot true and the outer face of the cover.
(http://i336.photobucket.com/albums/n354/klank_photo/inreversedjawstodospigot.jpg)
(http://i336.photobucket.com/albums/n354/klank_photo/afterturningspigotandouterface.jpg)
It was then pilot drilled through and the spigot counterbored for the piston rod gland.
The spigot could then be held in a collet, the main body brought to length and a register cut on (what is) the inner face to be a close fit in the inner face of the cylinder bore. The cylinder was brought up to try the "fit" repeatedly.
The outer diameter was then finished to match that on the cylinder casting, and the pilot hole then reamed for the piston rod.
Once again, all of these operations must be carried out at the same set up to ensure concentricity and the register/face is at 90 degrees to the piston rod reamed hole. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Turnedregisterandreamed.jpg)
The outer end cover next - a slightly more difficult item as it doesn't have a spigot - I'll do that tomorrow.
Thanks for the encouragement
Peter
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Hi Stuart,
I just saw your post after finishing today's post on the build.
Thank you for giving the link to the back stop.
Wow, you didn't hang around doing your boiler - glad it all worked first time for you.
Good luck with the class 4.
Peter
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Thanks Peter
as I have said I am mobility challenged from the waist down but ok above the belt , as I gave up work ( retired ) at 50 that was 15 years ago I have plenty of time , but I do have to work when the pain is under control
BTW your build is coming along at a good pace also , I do agree with others it is sometimes quicker and cheaper to use bar stock , but as Doris came from GLR i am familiar with there castings with the loco build you have no choice ( i think when I got the cylinder castings they cost the same as your Tina kit but they were fully core as per full size ) nut of the OT I will not clutter up your thread
Stuart
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In the latest copy of Model Engineer no 4404 vol 206 an article by the editor on machining a similar cylinder using a Keats angle plate. There is more than one way to cook eggs.
If you have one DO make sure that the base is square to the vee. If its not correct it before you need it.
Pete
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Loco,
I had a look around the Warco site but couldn't find any Keats plates, but there was this one, which is similar, but a little limited at how small an item it can hold.
http://www.warco.co.uk/Cylinder-Clamp-6798081E8B.aspx
Bogs
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volume 4402 features how do make the cheap chinese version accurate.
I will check mine tomorrow to see how small a piece it will take. These can also be used on the mill as well as a faceplate.
Pete
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The boiler - The final instalment.
The original drawings were on A2 and are fine except that no bushes are shown on the tube plate and that safety valve. The bush sizes are shown later and should be 5/16 x 32 as should the connector and nut. They are shown as 26 tpi as at the time Kennions had a lot of 26tpi fittings but 32 tpi is better and also allows fittings to be lined up easier.
Stan Bray used these drawings to write the article and it contains the reprints. Somehow there is no drawing of the bushes, just a mention in passing but at least you can make the boiler from them.
Round about 2005 Willie Schneeberger in Germany decided to improve matters by redrawing the whole lot on CAD and on A4 sheets. I perused them and considered them a load of **************. I produced a long list of corrections but from what I have seen they were never altered and these are the ones sent out - warts and all.
If you have a set of these contact me off line and I will send you a copy privately as I do not wish to put them here. The enclosed drawing shows the position of the bushes. Do not put the lower water gauge bush any lower as there will be little enough water over the boiler crown. The correct water level is 1/2 to 2/3 of a glass.
The bushes for the top tubeplate should be od 9/16, spigot od 7/16 and threaded 5/16 and those on the front are od 7/16, spigot 5/16 and threaded 1/4 x 40. If you follow Stan's 'words and music' you WILL get a successful boiler.
Anyone who really has a difficulty then please contact me off line and I will so my best to help you. Perhaps builders and prospective builders could print these jottings out and fix them to the drawings. Still to come - what it really looks like.
Pete
ps Drawing to follow
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(http://i1229.photobucket.com/albums/ee476/loco1475/P1000098.jpg)
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(http://i1229.photobucket.com/albums/ee476/loco1475/Image97.jpg)
THATS ALL FOLKS :lol:
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Sorry,
forgot to mention that ALL bushes must be made from Bronze or gunmetal and NEVER brass,
Pete
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A couple of set backs this last week.
My internet connection was severed (literally) by a back hoe on a JCB - my little town has embraced the need for a super sized supermarket to be built in what was formerly the town centre car-park. Utter chaos now.
That severence blew out the local server for my internet provider - and after about ten phone calls to Bombay seeking technical help (for which you have to pay for the privilege), I was told that the network was supposedly restored. It took nearly 7 days to sort!
The outer cylinder end-cover has no chucking piece and is somewhat risky to hold in the three jaw, given the "coning" of the outer edges.
SB recommends cleaning it up a bit and trying to get it to run as true as possible in the three jaw. Then centre drill and tap it 2BA and make up a similarly threaded stub mandrel from a bit of scrap bronze or gun metal bar and screw it into the "domed" side of the outer cover :-
(http://i336.photobucket.com/albums/n354/klank_photo/spigotandoutercover.jpg)
This then provides a temporary chucking piece to machine the outer circumference true and to dimension, the inner (flat) face, bring it to thickness and machine the register on it.
The stub can then be unscrewed and the cover reversed, the stub screwed back in, and the outer (domed) face machined. The dome can be finished (bar final finish/polishing etc.) by careful twiddling of the top and cross slides.
The stub is then sawn off flush with the inner (flat) face. :-
(http://i336.photobucket.com/albums/n354/klank_photo/finishedoutercover.jpg)
The original plan calls for just 6 (7BA) fixings for the end covers to the cylinder block. To my mind, this does not look quite right.
SB goes a bit overboard in his build, doing 24 (!!!) 10 BA holes at each end - with my luck, a sure fire recipe for a thin tap to break off somewhere.
I opted to go for 8 (7BA) fixings.
I marked out and drilled them in the end covers using my rotary table with home made chuck adapter/receiver.
The cylinder ends were spotted through and drilled/tapped. It is worth using a small "T" piece type hand tap holder and a bush to centre the tap. Assuming all of the holes in the cylinder block are all to the same depth, count the number of turns of the tap until slight resistence is felt for tapping the first hole. Then stop!! You now know (theoretically!) how many turns each of the others should take - just a safety tip. For those of you reading this and thinking of building the same - for a depth of about 5.5mm, it takes 19 half turns! (I guess someone can work out the maths based on thread pitch etc.)
Then setback number two.
I successfully milled the three finger shaped steam ports in the valve face of the cyl. casting. I used my height gauge to mark out accurately.
Dimensions are given for milling a small "pocket" at each end face of the cylinder casting, adjacent to its valve face.
From these, three holes are drilled at each end at 30 degrees to meet the steam ports.
The first (inboard) end went reasonably well.
I was using a 1/8" Clarkson type two flute cutter (on a 1/4" shank) to mill the marked out pocket.
Stupidly, without realising how bad this is - I used my trusty set of ER32 metric collets - essentially forcing the 1/4" shank into a 6mm collet.
Without realising it, I had fractured the shank as I tightened up the collet ring at the junction of the plain part to the clarkson threaded part of the shank.
Fairly obvious to all you experienced builders - but I have learned - metric collet = metric cutter. Don't force an imperial one into a collet that's basically too small - especially a Clarkson one! I used an ER32 "5-6mm" collet - I should have used the "6-7mm" collet.
As I was milling the pocket, I realised the cutter seemed to be too deep. The fractured end was walking out of the collet. I ended up with a pocket 2mm too deep at one point. This would have repurcussions with the piston stroke.
The only way to retrieve the situation (apart from buying a replacemnt cyl. casting - cost around £40!!!) was to do a "dentist" job.
I milled out the pocket square and silver soldered a piece of scrap gun metal roughly filed to size into the enlarged pocket.
The cylinder was then set up again in the Keats angle plate, with the "good" end outermost. It was set up to turn true with a clock on the inner bore and then the inner end re-bored very carefully to remove the overspill of material and silver solder.
The three steam passages were then drilled. :-
(http://i336.photobucket.com/albums/n354/klank_photo/NewPocket.jpg)
I was a bit close to one of the tapped holes for the end cover - but all is well.
You can just see the "seam" below the pocket in the bore.
The final item was the piston rod stuffing gland - nothing appeared to be provided for this in my kit of parts (the plans said this is made from a casting!), so I turned it up from a short length of 19mm bronze bar. :-
(http://i336.photobucket.com/albums/n354/klank_photo/CylCoversGland.jpg)
Slide bars next.
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Hi Peter
Glad to see your still on building the engine :thumbup: ,,,,, good idea making a chucking piece so you could hold the cylinder cover :med:
Keep it coming Rob
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Very nice build :clap: :clap: :thumbup:
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Peter
Digging holes can land you in lots of trouble, the spread of the hyper markets its a curse on us all.
Nice work with the cylinder, mandrels are one of my favorate aids. :ddb: :headbang:
Stew
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Peter
I am taking a particular interest in your build as I have the castings for the same build. Is it an optical delusion or are the PCD's of the holes on the cylinder ends at a different pitch? The plan shows the cylinder ends at 1 3/4" diameter, but my casting is not completely cleaned up and it's less than that already. I will have to stick a piece onto one of the feet as the caster must have had a new belt on his sander and been a little too enthusiastic.
I have made an excel speadsheet whereby you enter the fractions in one column and metric dimensions are churned out in another. This sheet is then kept with the drawings for constant referral. :)
Pete
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Thanks Stew, Benni and Rob - I appreciate the encouragement.
Pete - yup, you spotted my unfortunate error.
The casting as provided had a rough bore, a little out of true with the shoulders of the casting - particularly so at the "outboard" end. It was only after finishing the bore as shown that this became more evident.
I should have originally set up to bore the casting, based on the casting's shoulders as a sort of datum, rather than taking the centre(ish) of the wood filled original bore.
After completing the cylinder bore, I machined the outboard end shoulder at the same setting as for the bore itself, to get it to look better - but the outer shoulder diameter, once round and true had reduced by a couple of mm. from what it should have been.
I made the outer cover to fit, but had to reduce the PCD for the bolt holes accordingly. So, yes, one end cover is slightly smaller than the other, with a reduced PCD.
A mistake I have learned from for the future.
This error in original setting up was pointed out to me by a friend - but I didn't really understand what was meant at the time.
There is an article in the recent ME about doing this sort of det up properly properly, by Dave Clarke - when he machined the cylinder casting for a "Monarch" engine. I wish I had read that in time and understood that the way I went about it was wrong!
As a legacy of reducing the PCD - I may have a latent problem now in steam leakage around one of the securing studs being too close to the steam "pocket" edge. I shall possibly have to deal with that later!
Anyway - I do hope my mistakes may help you avoid doing the wrong set up.
Best wishes
Peter
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Anyway - I do hope my mistakes may help you avoid doing the wrong set up.
Peter
Thanks for sharing the info. I do have to learn from the mistakes of others, as I do not have enough time left to learn from just my own. :thumbup:
Pete
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Just a few bits to add - its been very very hot in the garage/workshop - we're in a bit of a drought down here.
The piston rod crosshead is machined out of a piece of 1/2" sq. bar :-
(http://i336.photobucket.com/albums/n354/klank_photo/startingcrosshead.jpg)
Machining is quite straightforward - ends up like this :-
(http://i336.photobucket.com/albums/n354/klank_photo/crosshead.jpg)
I should add that the "rounded" inner face of the fork needs to be fully "squared off" afterwards - or the little end of the piston rod will not fit properly.
The slide bars are machined from two pairs of castings - two each of tops and bottoms - bolted together, but held apart by 1/8" brass spacers.
The main points to watch are that the slide faces, both in the vertical and horizontal plane are truly at right angles and that the lower horizontal face of each is exactly the same and at centre height of the cylinder, less half the thickness of the crosshead slipper.
I machined the lower slidebars together in the milling vice, using parallels and a spacer between them. :-
(http://i336.photobucket.com/albums/n354/klank_photo/machiningslidebars.jpg)
The slippers are againg machined from the remaining (supplied) 1/2" square bar stock.
They are, I suppose, like a pair of thin T nuts, with a blind hole inset in the base part.
To ensure concentricity, I marked out the centre point of the hole using an optical centre pop, but then, having set the work up in the milling vice, cross checked using a laser edge/centre finder in the drill chuck and finding centre by dial reading from the edges. You can just make out the laser dot on the right hand slipper :-
(http://i336.photobucket.com/albums/n354/klank_photo/spottingslipper.jpg)
The hole, according to the plan is supposed to be "reamed" 3/16" to a depth of 4mm!
I used a 3/16" drill after pilot drilling and finished with a "D" bit.
I then tried a "dry run" to fit some components together prior to final marking out for drilling/tapping the baseplate. :-
(http://i336.photobucket.com/albums/n354/klank_photo/crossheadslidebarassembly.jpg)
At last its starting to look like an engine!
Best wishes
Peter
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Its taken a little while to pluck up courage to write this next chapter, but a good friend suggested I should, in order that it MIGHT prevent other beginners from making the (potentially very) harmful mistake(s) I have recently achieved.
For those more experienced builders who may read this - look kindly upon me please - I made a complete male chicken of the flywheel and nearly killed myself!
Here goes.
Having seen all of the recent really beautiful engines being built, I decided that before I carried on with the build, I should make the finish on my flywheel look a bit more professional. It will be painted later, but compared to other engines on display, I could do a lot better.
It ran quite true - no sign of wobble, but the surface finish on the shoulders of the rim and spoke web was poor. Probably as a result of tool chatter and not using HSS tooling (I don't want to get into the argument of tipped vs. HSS tooling here).
Anyway, I set up the flywheel again in my 5" four jaw with the jaws reversed, clocked it true to the outer rim and tried to gently skim the offending area on the side of the rim first.
The flywheel is approx. 6" dia, and the chuck scrolls were not on their limits. However, I put some "squashy" plastic card packing under each jaw to prevent marking the rim.
I was using a right hand tool, bringing it towards me across the rim shoulder with very light cuts only at about 350 rpm. A nice hissing noise, with fine dust being produced.
I got to the end of the final cut, and just as the tool met the corner of the edge of the shoulder/rim face, I became aware of something coming rapidly at my face.
Now I do wear protective kit :- safety 'specs, a heavy leather chest apron and a hide gauntlet on my left hand (hot swarf protection).
I moved my head to the right without thinking and the flywheel, spinning like a gyroscope, struck me on the left side of my chin, ran down the side of my throat, bounced off my collar bone and landed, spinning, on my left foot! At the time there was no pain.
I picked it up - no obvious damage, and decided to go indoors and get a cuppa tea.
My wife asked about "all of that blood on your neck!" and realized then that the rim corner - as sharp as a scalpel, had left a fine cut all down my neck.
Just a fraction deeper - is that where my jugular is?
Anyway - my completely stupid errors - learned a lot from this! :-
I should have used copper or thin aluminium packing (drinks' can or some such) under the jaws.
The tool should have been going away from me.
I should have brought up the tailstock with a centre in it, against the hub of the wheel.
I guess I was lucky (this time!.
Yes - I should have done it better - but I did not realise the potential for injury/damage with the wrong set up!
Anyway, I re-machined the rim shoulders again on each side (doing it the correct way and with better non-slip packing), and realised that overall, the thickness of the 'wheel was a little less than it should be.
As a "sop" to my stupidity, and to give the engine a bit more texture (and try and replace some of the missing inertia of a fatter 'wheel) - I sourced a small cast iron flywheel from RDG Tools (usual disclaimer). They are selling off some surplus Stuart cast iron 'wheels of various sizes at quite attractive pricing.
I machined this to resemble a grooved pulley wheel to drive steel ropework, and mounted it on the overhang of the crankshaft with a key. Not my idea I must hasten to add - I have seen other competed Tina engines with this "extra" - but it does add a bit more to the overall look of the thing I think. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Newflywheel1.jpg)
(http://i336.photobucket.com/albums/n354/klank_photo/NewFlywheel2.jpg)
A sobering episode!
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At least you are ok :D :D :D :D
You can always see the mistakes after they happen
I had a small truck flywheel come out of a chuck at work years ago the ring gear climbed up the wall :bugeye: :bugeye:, scares me to death thinking about it now.
Engine is looking great :) :) :)
John
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Hi Pleased you lived to tell the tail its always worth relating such incident as others can also learn from them.
I had a similar things happen with a fly wheel but this time it flew of an engine, I decided to experiment by adding a ball bearing to the rocker engine I built, the fly wheel is only small about 2" Dia and i stuck the bearing on with loctite, well the bearing worked a treat it ran like the clapers, then the fly wheel flew off (is that why they call them fly wheels :scratch:) ) did a couple a laps of the shop and crashed against the door, it could quite easily have taken by eye out.
Your engine is looking a treat I like the aditional drive pully, nice work.
:clap: :clap: :clap:
Stew
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John, Stew - thankyou both for the kind words and encouragement.
Just when you think you are doing well - you can get a bite on the bum! Sobering to realise what potential for injury/damage there is in what we do!
What you said is much appreciated.
Peter
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Finally - I got round to the valve chest components.
Here is the valve chest casting as supplied. :-
(http://i336.photobucket.com/albums/n354/klank_photo/alvechestcasting.jpg)
I rather liked the slightly "raised" pad on the side where the steam inlet piping will go and decided to keep it and make it a little more prominent.
After some basic machining in the 4 jaw and mill I ended up with this - ready for drilling/counter drilling for the valve rod gland. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Basicmachining.jpg)
Here is the set up for drilling the 1/4" (blind) hole (for the gland bush), having marked out and popped the mark for the valve spindle - clocking it with a wobbler - SB recommended using washers to protect the larger faces of the valve chest and allow the jaws to grip over the centre recess.
The hole was finished with a D bit :-
(http://i336.photobucket.com/albums/n354/klank_photo/setupfordrilling.jpg)
No material appeared to be supplied for the valve spindle gland itself, so I turned one from a length of bronze bar and filed the flange to match the shape of the larger shoulder on the end of the valve chest.
The 1/8" hole for the valve spindle was drilled/reamed in the 4 jaw with the gland fitted and secured to the chest with two studs and washers.
The "packing" in the 1/4" gland hole is a neoprene O ring (supplied).
Sorry about the camera shake! :-
(http://i336.photobucket.com/albums/n354/klank_photo/finishedwithgland.jpg)
The really time consuming/fiddly bit next - making the cover, marking out for the stud holes, drilling/tapping everything and cutting/finishing the studs.
According to the plan, the valve chest cover is a gun-metal casting, but nowadays, a length of brass flat is supplied.
The original plan shows a shallow (1/16") pocket/recess machined into the inside face of the cover, lining up with the area of the valve chest swept by the slide valve.
I was told by GLR that this pocket is no longer necessary - just "make the lid out of the brass flat!"
If anyone reading this who knows about these things - is the shallow pocket important? I don't know - it was obviously put there originally. Does it make the running of the valve more efficient under steam?
I suppose the flat brass "lid" outer surface lends itself to some "embellishment" - HH, in his later build of Tina, etched his initials into the surface - looks very nice! There is a good article on etching in the current issue of MEW.
The original plan calls for 8 x 7BA studs - which SB thinks a little too basic and unprototypical.
After much measuring and head scratching, I marked out for 14 x 8BA studs - but at this time, only drilled for 13 of them.
I am not certain yet what type of union to drill/tap for in the steam inlet pad, and I don't know how much "meat" I will have to play with for the centre stud hole in the upper side of the valve chest. I don't want to end up drilling into a steam passageway.
I ensured my hole spacings would not intrude into the angled internal steam ports in the cylinder.
The really fiddly bit was finishing to length all of the studs from 8BA allthread. I really should get around to making a screw/stud cutting - to - length - jig - useful for all of the myriad of studs needed in an engine!
Anyway - here is the cylinder with valve chest and cover temporarily mounted, minus one stud hole! :-
(http://i336.photobucket.com/albums/n354/klank_photo/mountedwithcover.jpg)
The valve and steam chests DO line up properly - there is a shadow on the edge of the left hand side of the steam chest where there is a slight casting flaw on the face/edge of the port face of the cylinder!
Maybe I'll have a go at the valve eccentric and strap tomorrow.
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:drool: Hi Peter :bow: :bow: :bow: :bow: doing a grand job :clap: :clap: :clap:
You sure have made good head way since i last looked in :bugeye:
Rob
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Hi Peter
I really like the second flywheel idea
Ive never seen it before :clap: :clap:
Pete :wave:
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Rob, Pete,
Thanks for the encouragement - you make much better engines with no mistakes!
Peter
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It's looking very good, keep up with your'e good work. :thumbup:
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Thank you Benni - sorry about the delay in replying - some domestic issues cropped up and I haven't really been able to get much done in the workshop.
Not a great deal to show - but here's whats been done recently.
There were two gunmetal castings for the valve supplied in the kit! The "spare" is shown in the photo.
Anyway - it is a fairly straightforward job to finish this - using the four jaw to bring it square/to size, and then some careful milling to finish the valve pocket on the underside and the slots for the valve rod and nut.
As it says in the instructions by SB, it is essential to get the slot for the nut spot on in size and truly square to the valve body.
The slot for the valve rod was very carefully marked, popped and drilled through first in the four jaw, then using the mill to make the slot down into the drilled chanel.
No material appeared to be supplied for the nut - this was machined from a piece of scrap brass bar - once again the tapped hole (5BA) being marked and drilled with care. The valve rod is from 1/8" stainless steel (supplied), threaded 5BA each end :-
(http://i336.photobucket.com/albums/n354/klank_photo/valverodandnut.jpg)
The valve rod cross head is a straightforward machining job from 1/4" mild steel bar as supplied. The plan is a bit "off" in that it shows the crosshead tapped 6BA - it should be 5BA! :-
(http://i336.photobucket.com/albums/n354/klank_photo/Valverodcomponents.jpg)
Both eccentrics are machined from a generous length of 1" mild steel bar suppled.
The one for the water pump is straightforward to machine using a parting tool blade/rear tool post :-
(http://i336.photobucket.com/albums/n354/klank_photo/Groovingforstecc.jpg)
I made the two eccentrics seperately - marking out the off-set and drilling/reaming for the crankshaft in the four jaw after setting them to run true around the popped mark.
Parting off whilst eccentrically mounted in the four jaw was interesting - a sort of "interrupted cut" - but the tool blade finishes up nicely into the reamed hole.
The eccentric for the valve also includes a collar to take the securing grub screw - which makes adjustment of the valve timing a lot easier - without having to de-mount the eccentric strap each time an adjustment is necessary if the eccentric were secured by a grub screw through its main body - which IS the case for the pump eccentric. I suspect setting the pump travel is a much easier exersize, so its not such a chore.
Here are the results (yet to be cross drilled/tapped) with the castings supplied for the straps. :-
(http://i336.photobucket.com/albums/n354/klank_photo/Finishedeccsplusstrapcastings.jpg)
I'll do the straps next.
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After a little filing,squaring up and such, the strap castings were drilled through for 7BA tapping size in each shoulder, and split as per the plan using a fine slitting saw - gently!
Not forgetting to centre pop the mating halves to avoid confusion later!
The lower (squre) segments were tapped and the uppers (curved) drilled through clearance and the two halves bolted together with the (supplied) small hex headed 7 BA screws.
I appreciate this is all pretty basic stuff for many - but for beginners - its not so daunting.
Each prepared strap then needs boring out to the actual diameter and facing/thinning to the size of its respective eccentric, plus a tiny whisker.
I chose to use the four jaw, fitting up a back-stop to support the rear face of each strap.
In the SB article, the centre is found using a fixed pointer to get the casting hole "sort of where you want it" - if it works for you, then fine. I don't like that and would prefer to mark properly the centre point.
I find the quickest and easiest way is to fill the casting hole with candle wax :-
(http://i336.photobucket.com/albums/n354/klank_photo/waxcasting.jpg)
(http://i336.photobucket.com/albums/n354/klank_photo/melted.jpg)
I just "caressed" the knob of wax with a very low propane torch (any heat source will do - even a hair drier!).
When the wax is nearly set, I gently rub the face along a flat plastic surface to finish it off.
Any mistakes can be easily rectified with a few dribbles from the candle!
The correct centre point from the plan can then be gently scribed and the point gently popped with the pointy bit of the scriber. (Just think classical Latin/Greek writings! - the result is quite resilient).
The strap can then be set up in the 4 jaw in the usual fashion using a wobbler in the centre point. (Just be a tad more gentle when setting it up). :-
(http://i336.photobucket.com/albums/n354/klank_photo/centering.jpg)
The bore can now be machined - I use a Glanze boring bar in a home made holder. The wax comes away quite easily!
After boring to size, the face can be finished and bought to near size for thickness. :-
(http://i336.photobucket.com/albums/n354/klank_photo/startingbore.jpg)
The strap is then turned around in the 4 jaw putting the machined face against the backstop, and the other face machined to size to fit the eccentric.
Here's the result - awaiting final finishing. :-
(http://i336.photobucket.com/albums/n354/klank_photo/awaitingfinishing.jpg)
I always build - up as I go to ensure everything fits and works together, but leave the final surface (cosmetic finish) to the end of the build - just in case of accidents when handling!
The next job is the valve and pump rods.
The original plan calls for these to be simply made from flat bar stock - functional but looking a bit basic!
There are plans given - to a certain extent, one page is missing! - to fit alternative tapered, round rods in place of the originals. Fitting these to the eccentric strap - buckles looks a bit of a job - involving milling out a pair of steel square shaped forks to fit around the gun metal tongues on the straps. Need some thoughts on this.
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That candle trick is really neat! I'll be borrow-- stealing it! :thumbup: :thumbup: :thumbup:
It's coming along nicely.
Ron
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Thanks Ron - you're more than welcome.
Its probably been done before, I am sure its not original - but I was stuck for a means of "filler" on my first ever engine eccentric - and wax from an old candle seemed a viable option - its worked fine. I also used wax on its cylinder bore (the ever popular Stuart 10H).