Building a 31/2" Gauge Locomotive Engine

[sbwhart]

Ok Chaps Her's my starter for ten

The Loco is a 2-4-0 LNWR Precedent Class to LBSC's Mabel Design. Hers a photo of a model built by a chap in Canada



I choose a LNWR loco because both my Grandfather and Great Grandfather had both been loco drivers with the Company. LBSC otherwise known a Curly Lawrence serialised the construction in Model Engineer in the sixties, just before died, his last of over fifty model loco designs. The Precedent class of Loco earned the nick name JUMBO by its crews from its power and work rate, with one engine HARDWICK clocking up over 2 million miles in just over ten years, this Loco is know preserved at the national railway museum in York. I like the idea that my predecessor may have drove this engine

I bought a set of castings and drawings from Reeves and being on the lazy side ordered set of laser cut frames from another company this saved me a fair bit of work (and hacksaw blades) as they also marked out all the holes positions.




I held off with the boiler, agonising over this safety critical component, : the thought of making a boiler scared the sh1t out of me, A commercially made boiler would cost about £1000 whilst the bits to make one would be about £350. I joined my local model-engineering club (South Cheshire Model Engineering Society http://www.southcheshiremes.com ). A lot of the chaps at the society have built quite a few Locos and have loads of experience with boilers  , they convinced me that I could build my own boiler and that they would help, if all goes to plan I should be starting my boiler in the summer:- so watch this space.

Have Fun

 

Sew

[sbwhart]

To bring you up to date I'll load up some photos of the build to date most of the photos will be selve explanitry. As with most things there is more than one way to do a job this is just the way I did it, there are probibly better ways, the important thing is to do it safely and to have fun.

Cutting slot in buffers beams, the beams are clamped together a a pair so that they are exactly the same



Milling up the outside of the hornblocks



Milling the horn blocks up to take the bearing. The horn blocks a riveted to the frames and the frames temporary riveted together back to back so that everything lines up axactly, you rivet the frames together for drilling holes ect so everything lines upexact





Making the bearing blocks again you have to ensure that the blocks assemble into the horn blocks in the same way as they were machined so that the holes line up for the axles. 

[sbwhart]

The buffer had angle brackets riveted to them I tried brazing but a trial run on some scrap resulted in failure I couldn't get enough heat out of my kit so riveting it was.

The beam was then clamped together on the main strecher frames and when everything was nice a square, checked by measuring the diagonals, the fixing holes were spotted through onto the buffer beam and the lot screwed together.



Next job was the wheels thse were turned up on a sacrifical face plate and a mandrel so that they were all exactly the same size.

[sbwhart]

The axles are made from ground mild steel bar, which was set up to run dead true in four jaw both end centred and the diameter turned between centres for a push fit on the wheels. The crank anxle was made up in sections:(sorry no photos) the section were glued together with high strength loctite and pinned after assembly, it takes about 30 seconds to go off so it gives you a chance to get things lined up, to get things at 90 deg I used a set of 1"2"3" blocks these are realy andy bit of kit to have round the shop.



The wheels were drilled for the crank pins using a simple jig so that they were all the same the crank pins again were turned up as a push fit in the wheels and fixed with high strenght loctite I'll pin them at a later date when I know everything is OK, the wheels were quatered on the axles using the 1 2 3 blocks and a set square a bit of a fiddle where you wish you had three hands  but with care and a bit of practice it can be done. 

[sbwhart]

Next bit was the coupling rods:- first job was to mark one rod out, then using a jig with a off set bush accuratly set it up on the wheel crank pin centres, checking that both sides are the same if you've got your quartering or your bearings wrong it will show up at this point.





Then use this jig to transfer the hole centres to your coupling rod: drill one hole in each rod than clamp them together with the jig and drill the other hole through both this way everything will match up.



The next part was to make a jig for milling out the rods, I had two attemps at this my first being a right cock up  the sucessful method was to locate off dowels in the crank holes this way everything came out on their centre line including the fluting.





The final job was to radius out the end I could have done these with a filing button, but I like to machine things out so I used my rotary table.





Hows it going so far chaps

I hope I'm not using up yo much memory with the photos

 

Cheers

[Bernd]

Ok Stew. On your first post I think you were nipping at the egg nog. I see you spelt your name without a "T" in it. 

Pics could be of the size you used showing the wheel being turned. Others are a bit small for veiwing detail.

Very nice looking engine by the way. It'll be nice to see it under steam.

Why are so many British engines made with inside cylinders? It would seem they would be hard on the maintance crew to service.

Bernd

[sbwhart]

Hi Bernd

Thanks for the comments I was a bit concerned that the big pics would gobble up too much memory but that's probibly me I don't understand these computer thingies very much I've no idea why they liked inside cylinders, with this particular loco the slide valves were inclined on an angle, this is what they atributed their power too, the steam having a more direct route into the cylinders, I don't know if this is correct or not.

The missing T you can atribute to unruley fingers that and my poor spelling:- spelling is somthing I've strugled with all my live, its probibly held me back a bit:- spell checker rules ok  speeking of which where is the a spell checker 

Cheers
 
Stew

[Bernd]

I don't think you need to worry about space for the pics. I'm sure the software will yell at you if it gets to be to much. 

What you said does make sense about a more direct route to to the cylinders.

I have a problem typing too. Sometimes the brain (all of 2 cells) are working faster than the fingers can type. I noticed my lack of spelling when I post. What's worse is my grammer and compousre of what I'm trying to say.

I had asked Eric about that to, spell checker. I sometimes will prepare a long post using my word processor and then just doing a "copy" to transfer the post to the board. Then I go and add the smilies aftwards.

Anyway, looking forward to more posts on that engine build. Just make the pics a bit bigger so we can see the detail. Now get with it.   

Bernd

[bogstandard]

Stew,

Very nice set of interesting articles.
 
I wouldn't worry too much about the spelling, if we can understand it, that is all that matters. Everyone has their own little problems, and you shouldn't let it hold you back on expressing yourself.

I usually set my picture size before uploading to bucket as x = 8" y = 6" for landscape pics and x = 6" y = 8" for portrait. At those sizes they are big enough to see, but not too big that you have to scroll the page to see all the piccy. By putting the pics into bucket and putting a link to it, saves a great deal of space on the site.

I personally must get back to putting pics into bucket first, as really I am being lazy just posting them straight into the article under 'additional options', I normally only use that for crap-o-cad sketches.

Nice one Sew

Bosg

[Brass_Machine]

Very nice Stew.

Worry not about the space for pictures. I still have plenty left!

As far as the spell check... that is coming guys. I need to move over to the dedicated server first. This is a shared server and the hosting company doesn't want to install the needed files for the spell checker to work with the SMF sofftware.

Eric

[sbwhart]

Hi Chaps

Tried resizing photos already posted but no mater what I did they ended up the same size

So here we go with the again:-

The excentrics were made from a 30mm dia cunk of mild steel they were turned up all together, and the off set hole set up by simply putting a piece of packing the correct size between a jaw and the work in the three Jaw chuck, the hole was drilled and reamed and the slices of excentric parted off making a few spare, I also retaining a piece of the finished bar to act as a gauge when I bored the sheeves:- Sorry no photos of this as I forgot to take them

The sheeves are made from phos bronze castings. The first job was to drill the castings for the clamping holes, then cut them in half, after cleaning the cut face up, the bottome half was tapped 6BA the top half opened up as clearance



The two halves were then clamped together:- Tip a small bush turned up the finished width of the excentric used as a washer, so that when you skim the excentric to width you leave a witness mark on the bush this way the holes will be in the midle, and sheeve the will outomaticaly be the correct width.

Set the sheeve up in the four jaw and bore out to a nice fit on the gauge. Then skim to width you can do this eather in the four jaw or set the piece you used as a gauge in the three jaw and tighten the sheeve on this using a piece of paper as packing.

[sbwhart]

Connecting rods

The connecting rods are made from mild steel, the first job was to mark out one rod, then to drill the little ends and to clamp the two rods together using this hole. With the two rods clamped together the rods were milled out.



The big end clamping bolt holes were drilled out with the rod set up on an angle plate,



 The big end caps were then cut off the rod, the cut face cleaned up and the hole in the cap opened out as clearance and the holes in the rod tapped 6BA, the caps were then screwed back onto the rods, and the hole for the big end bearing drilled out. The big end bearing is made from phosphore bronze, as this is a split bearing two chunk of material was milled in half, the two halves soldered together, and set up in the four jaw with the split on the centre, and the bearing turned, heating it up released the two halves. The little end bearing is just a plain bush held in place with high strength loctite.

Completed crank axle

[bogstandard]

Pictures are perfect size Stew, and the article is coming along nicely.

John

[Bernd]

Yup, the pics are great, 640 X 480 pixels, perfect.

Nice job on getting all the hardware between the frame. It'd be interesting to see that in motion.

Bernd

[Divided he ad]

Hi Stew,

Now since our brief (but fun) meeting at Boggies on friday I've been waiting for a post on the finished loco.... Only kiddin'    just the cylinder 


I've got to say it here too... Your a brave man for taking on such a build, not just the complexities more the dedication 

Looking forward to seeing it take shape as are a lot of people I think?


Ralph.

Oh and.....

Bernd....

Yup, the pics are great, 640 X 480 pixels, perfect.

  Does this mean my posts are too big??

I don't know if I could go about re-sizing everything.... That would take ages!! 

[sbwhart]

Hi Ralph

It was good meeting up with you only sorry I couldn't stick arround longer:- as it was it took an hour for the boss to speak to me,:------- only an hour I was banking on at least two


Obvoiusly I should have stayed longer

Got about 2 to 3 weeks work left on the cylinders then I'll post the build, in the mean time I'm not quite up to date with current progress, so I'll try and get it posted today.

How's the old finger engine going ?
 

Have
 
Fun

Stew

[sbwhart]

OK Chaps her's the first instalment for machining the cylinders

The two inside Cylinders are machined from the same casting, as are the steam ports



A set of cylinder castings were ordered from Reeves this included the cylinder casting the end covers the steam chest and the steam chest cover

First job was to check the castings over and clean off any flashing, they seamed OK. Before starting to cut metal I always like to read up as much as I can about how other people have gone about the job, from this research I work out a method, in my head, that I think will suite me and the kit I’ve got. It also gives you chance to work out which are the critical features, as is so often found the critical feature is more to do with square-ness and alignment, the size of the bore are not really that important as you can make the pistons to fit if any thing the finish in the bores is more important than the size. If the bores are not square to the frame and parallel to each other the motion will bind causing wear and excessive loading.

I decided to follow the method in good old Curley’s words and music. He recommends using a faceplate with an angle plate mounted on it, squaring the casting up on this and bringing to size. The positions of the cylinders are marked out by first plugging the bore with wood, then by putting a parallel between the cylinder and face plate and pushing the cylinder hard up against the parallel, will ensure that bores come out square a good sturdy clamp over the top keeps it in place on the angle plate, you can know move the angle plate about on the face plate and everything will stay square. Using your centre height gauge get one bore positioned, and to maintain vertical alignment clamp a parallel under the angle plate, so that when you come to do the second bore you just need to slide the angle plate along to get the horizontal position.

You need to add balance weights to the face plate to counteract the out of balance mass from the angle plate and casting, you can use anything you have at hand for this, I cast up some lead weights from some old lead piping I had, but lathe change gears will do just as well.







Averything went to plan first bore machined up great, then with the second bore I decided to try coolant to see if I could improve the finish:- Desaster the coolant pipe got jambed between the job and the boring bar resulting in three dirty great grooves in the bore

          

Will Bandit come to save the day watch this space for next weeks thrilling instalment

[Brass_Machine]

How are you going to fix the grooves?

Eric

[Bernd]

Oh and.....

Bernd....

Yup, the pics are great, 640 X 480 pixels, perfect.

  Does this mean my posts are too big??

I don't know if I could go about re-sizing everything.... That would take ages!! 

Ralph,

I don't think I want to go there.

Bernd

[Divided he ad]

Firstly.....    Grooves in your bore!!!! can you re-size?  That sounds like it could have been a heart stopper 


Secondly.... The finger engines will be coming along once I get the new materials.... Hopefully before the end of the week?


Thirdly, Bernd.... Good... I don't want to either 



Got to go to work now 



Ralph.

[bogstandard]

Stew,

If you still haven't got the groove issue sorted, pop around and I am sure I can find some PB for you to resleeve with.

John

[Darren]

Stew, that's not nice when it happens is it...

John, what a simple solution....thanks for sharing 

[John-Som]

Whilst waiting for my workshop to warm up this morning I read thro the build notes on your loco – very impressive, I am in awe !!!  I was particularly pleased to find your notes on machining the eccentrics. As this is what I shall be tackling this morning on my mill engine –

Tip a small bush turned up the finished width of the excentric used as a washer, so that when you skim the excentric to width you leave a witness mark on the bush this way the holes will be in the midle, and sheeve the will outomaticaly be the correct width.

These tips are little gems to those like me on a steep learning curve.

I am beginning to think there must be something in the Cheshire water that produces such talented engineers.

John S

[sbwhart]

Hi John and John S

Work has started to get in the way again I'll post the next chapter tonight.

John thanks for the offer of material to sleeve, but as you'l read I went another way.

John S pleased to be of help, I can't help but admire people who start this game off their own backs, with very little experience, and go on and produce some superb work, if I can help in any way please don't hesitate to ask.

Have
 
Fun

Stew

[bogstandard]

John,

I am beginning to think there must be something in the Cheshire water that produces such talented engineers

At one time in the not too distant past, I reckon about 80% of the male working population in this area was involved in engineering of some sort or another, railway works, Rolls-Royce (now Bentley Motors), Fodens and ERF (steam wagons and later, road haulage trucks), Royal Ordnance (munitions production), Midland Rollmakers (casting and machining steel mill rolls), plus all the small supporting industries etc. My wife even worked at Royal Ordnance for a time. So really we in this area have it in our blood, so if only a small few of the ones who were working in it took it up as a hobby, then we would automatically have a larger than normal percentage of model engineers.

Because of the large amounts of people who worked in the railway industry, or had some sort of connection with it, like Stew for instance, there is a thriving community who build and run model locomotives. The rest of us have a lean in other directions of model engineering.

John