Building a 31/2" Gauge Locomotive Engine

[Darren]

Nothing wrong with being long winded,

Another great post with some great pictures, just what we like to see.
As always very informative Stew, keep em coming....

[Bernd]

Excellent pics and write up of doing the slide valve. Much better than I did on the coke bottle thread.

I'm going to have to redo mine from a solid piece. I'm not happy with how it came out. Oh well.

Bernd

[SPiN Racing]

Very nice!

Love seeing these threads.


Scott

[sbwhart]

Hi Bernd

The slide valve set up is quite tolerant to variation, what you've got will probibly work fine, so I'd think twice about making from new, I'd try it fist.   

Stew

[Brass_Machine]

Stew is rocking this thing out! Nice job   

Like Spin said, I love these threads.

Excellent pics and write up of doing the slide valve. Much better than I did on the coke bottle thread.

I'm going to have to redo mine from a solid piece. I'm not happy with how it came out. Oh well.

Bernd

You will Bernd...   

[sbwhart]

Hi Chaps next instalment

Up to now my postings have covered work done over the past 18 months, this posting bring you up to date. The cylinder is more or less finished, I wont fit it between the frame until I've completed the motion works so that it goes in the correct position. Also the front covers need machining to take the slide bars, but again i'll wait until the motion works are complete, it being easyer to make the covers fit the slide valve than the slide valve fit the cover.

OK lets do it

Front and Back Covers

The covers and made from phosphor bronze casting, the stuffing gland being integral with the front covers, the casting come with a chucking piece.

The casting was set up in the three jaw, and the chucking piece diameter and the face skimmed up. Gripping by the chucking piece the outside diameter was turned up and the small stepped diameter turned to a nice snug fit in the cylinder.

The chucking piece was cut off, and to grip the cover a split bush was turned up.







The covers were stamped L and R.
The front covers were set up on the rotary table and the lozenge shape stuffing gland machined.




The position for the clamping holes were carefully measured and marked out, taking care not to drill into the steam ways, this is the reason for the uneven spacing, Tip:-  drill with the tapping drill first then when the cylinder has been drilled off the cover open out to clearance size, this way the holes will line up spot on. When I made my Beam Engine I drilled the clamp holes over the steam ways, so I had to hide this by having a dummy bolt, shhh don’t tell any one that’s my secret.

 To fit the covers onto the cylinders, they were gripped onto the cylinder and the surplus material marked, and filed off.



It is called for the clamping holes of the front covers to be countersunk. This was done using a little tungsten countersinking tool I bought from an exhibition, on a whim, as they looked handy and the price was right.



To transfer the holes to the cylinder the covers were fixed into position using two way tape, the cylinder drilled through the cover 5mm deep, I held the cylinder by hand on the base of the vice, the jaws were opened up out of the way. The cover removed and the holes carefully tapped 7BA. What’s the best way to remove the sticky left by the tape, I tried:- Meths, WD40 and Terpintine substitute, which I found the best. (you chaps may use something different)




Finishing off the Slide Valves

Cross bar:- The cross bar is made from 1/4” square mild steel. The two were made on one bar. Position marked and the hole centered and then drilled and tapped. Tip:- to ensure that the tap starts square: lightly grip the shank of the tap in the chuck, just enough to keep it square yet allowing it turn.







For the slide valve to work efficiently the surfaces need to be good and dead flat. To achieve this rub on progressively finer emery paper on a flat surface I use a square cube I rescued from a scrap skip, but a piece of plate glass or mirror will do.

[Divided he ad]

Looking good Stew 

Accuracy.... That's where it's at..... That's where I need to concentrate!


I would think it woulde be a while before I would attempt such a huge project.... I can barely find the time and patience for the ones I have to do now!!


One question, I've heard the term a few times but never found the time to investigate.... What's a stuffing gland do?



Looking forward to seeing the rest take shape.


Ralph.

[rleete]

A stuffing gland seals the rod so the cylinder can be double acting.  Thing packing like in an old fashioned faucet valve.

[sbwhart]

Hi Ralph Re Stuffing Gland

Simply a stuffing gland is method used to seal a shaft. It consists of a cord impregnated with: Graphite, PTFE, or some form of Wax, the cord is wound around the shaft, you then tighten the Gland nut down onto the cord compressing it and forming the seal.

The cylinder for my loco has four of these glands:- two on the steam chest and one for each cylinder.

Instead of piston rings you can use the cord to seal the pistons, but some people are know using PTFE sealing rings for this job.

The pic hopefull shows this



Have
 
fun

Stew

[Divided he ad]

Ahh!! (enter light bulb smiley here!!) 


I've got it now. Thank you guys 


Roger...

Thing packing like in an old fashioned faucet valve.

 
I'm not old enough to have ever stripped down or possibly even used one of those 



Still, I have a firm grasp on the concept now 


Looks like that there chest is very near done Stew?



Ralph.

[sbwhart]

Hi Ralph

Yes Chest more or less done,  just got to make the stuffing nuts for the piston, for that I need to order a 3/8" * 40 ME die, thought I had one but no, still when you've got it you've got it. 

Have

fun

Stew

[bogstandard]

Got one you can borrow if you want Stew.

John

[sbwhart]

Thanks John
 

I'll pop round Tuesday night if thats ok, Jammy donuts on me. 

Cheers

Stew

[sbwhart]

Hi Chaps

Its getting near the time when I'll start on the old loco project again, I think I'm nearly over my bad dose of 

and I've had a couple of  from Ralph.

I'm going to set myselve the objective of completing the valve gear for my loco, and hopfully get the it running on air.

The loco uses the Allen straight link valve gear which is an adaptations of the Stephenson and the Gouch system the main advantage of the Allen gear is that it was easyer to manufacture, I'm sounding very knowlegable arn't I but I've just read that in a book, Loco valve gears are a huge subject on their own over 40 systems were in use.

This is the valve gear for my loco and I tried attaching an animation of it but the file was too large so you'll have to Google it yourselve



So watch this space

Stew

[Divided he ad]

It's about Bl@#*/y time    



Good to see your thinking about this again Stew.... It's just that I want to come see it running in a few weeks..... Waht? That's not likely.....?  I think you'd best get your skates on   


Seriously.... a few months then 



Eager to see this beastie take shape Stew.... However long it takes   




.... Seen this?   


you have now 




Ralph.

[sbwhart]

Hi Ralph

You can pop round tomorrow and see the progress so far if you've got time.

where did this come from 

Like it

 

Stew

[sbwhart]

Choo Choo I'm back on the Loco Project

          

        

First job finish of the eccentric straps by fixing the arms to the straps

The important feature with the assembly is that you get the hole centres on all four exactly the same to do this you have to make an assembly jig.

So first job a crib sheet and crap O cad of the jig.



I'm going to use a chunk of ally that I picked up from the scrapy that I've used a number of times for bits of jigs and fixtures so its got a few holes in it already but I can work round these, and a piece of the bar left over when I made the eccentrics and put aside for this job, its a nice fit on the straps.



The chunk of ally was squared up with a flycutter



At a suitable distance from one end a 5mm drill was put right through then a 9.5mm drill 10mm deep followed by a 10mm drill, then using the hand wheel dials the table was moved the exact hole centre distance (58.74mm) a 3mm hole was drilled 10mm deep followed by a 1/8 drill.



The piece of bar was chucked up true in the lathe and and a short length turned down to 10mm a nice fit in the ally, it was also drilled and tapped through M5 and parted of to a suitable length sorry no pics of this.



Some big washers were modified as clamps and that was the jig done.

The eccentric straps are riveted to the arms so the first job was to mark out the position for the holes and drill 1/16 I,m drilling the holes before doing the slots because I'll have more thickness of metel, to drill after they are slotted could result in them bending. To hold the straps for drilling and slotting I used the assembly jig.

Setting the strap square in the jig



Drilling the 1/16 hole

Finding the

Finding the edge of the slot with fag paper:- DRO zeroed and head lowered by half the total thickness of the cutter and the strap to bring the cutter on centre.



Milling the slot with a 2mm slitting saw



And thats the straps finished.

Next job was to rough out the arms, I decided to do all four arms together I cut out some steel strip and stuck them together with two way sticky tape to make a pack. The pack wa squared up and a 3mm hole drilled through one end and a 3mm dowel loctited in place to keep everything together.









Then by twidleing the handles the straps wer roughed out





Well thats the lot for tonight next job will be silver soldering a block onto the arms so that a fork can be milled into the ends

Have Fun

Stew

[Divided he ad]

Nice workings there Stew


I've never had to make such before but may do one day?

The holding jig is a thing worth remembering, that's the kind of stuff that comes in usefull all over the place




Glad your back on the job too       







Ralph.

[SPiN Racing]

Very Cool...

For Loco Noobs like me its going to be interesting reading.  Watching the loco threads.... 

[sbwhart]

Had  a bit of shop time this afternoon so decided to silver solder eccentric arms for the fork.

I seem to have accumulated quite a few way to heat things up.



On the left in the red tank is Propane torch I've had this set up for about 12 months and not used it yet, I got it to solder the loco boiler together

Next to this is a small welding system its not an acetaline system, its supposed to be similar, I bought it to braze the frame of my loco but I just couldn't get enough heat into the metal so ended up riveting it together.

Next is a Plumbers butane soldering torch this work well for silver soldering but the blast is a bit fears, it can blow light items about a bit.

At the front is a small pencil torch you charge up with lighter gas, OK for realy small soft soldering bits.

For this job I'm going to use the new propane torch.

First a bit of safety.

You need to be carful with gas cylinders make sure your using the correct regulators etc.
Make sure you havn't any other cylinders, airosols, and combustable items about where your doing the job.
Wear safety glasses in case you gat a splash. Wear Leather gloves.
And put a bend on the end of the solder rod to let you know which is the end to pick it up buy, the other end will be hot.

This is my hearth made up from fire bricks.



Preparation of the work piece is important you need to get the faces cleaned back to bare metal and silver solder works by capillary action so I've put four nice deep centre pops on one of the mating faces so that a small gap is formed for the solder to flow into, I,m using easy flow flux and easy flow 55 silver solder. I've also got some pliers and tweezers and a piece of wire to lift, move and poke the hot bits



A liberal dose of flux was dolloped between the bits and a small length solder placed on the joint.



The torch was fired up and the flame directed on the thick end of the work away from the solder, the solder will flow towards the heat when it melts, you have to be carful thing don't move, if they do tease them back in place with the wire, you can add a bit more solder by holding the rod on the work if you think it needs it, keep the flame on to get a nice uniform heat to let the solder flow, not too long or you can spoil the solder, let the job cool down for a few minutes then you can quench it in water.

This is the result you can see where the solder is showing all around the edge of the work.



I've been having seconds thoughts    about making these arms this way it may have been better to have milled them from solid  I've got this far so I'll see how it goes.

Stew

[sbwhart]

Had an hours shop time today so started on finishing the arms off to shape I'm doing this with the old mark 1 milling machine the trusty hand file.

So that the radi would look ok I made some filing butons these are simply bushes turned to the required diameter, I made one bush as a nut and the other as a bolt, I simply put a screwdriver slot in the bolt to tighten things up,

Griping the button in my refurbished small vice 



This is how the buttons assembled on the arm



30 minutes work with diferent shaped files and this is what you get.



Still needs a bit of tidying up but I'm quite happy with the result and I can see from the cleaned edge that the silver solder has penitrated right across the joint.

Stew

[shoey51]

this is a great looking project
well done

[NickG]

They are great Stew,

Sometimes I think we get the blinkers on and think we have to mill everything, we forget we have files and vices! I certainly do!

Nick

[Divided he ad]

Yes! Yes.... Mill everything!!    


Oh... Ok, filing has it's place too, I hand shaped the aluminium base plate to my finger engine and often draw file parts to get the shape/finish I want 


Nice looking parts coming there Stew.... Gonna look great when they're finished and in place 


Now, Did you see that rolling rail for the loco? .... How cool was that!? When you get far enough one of them must be on the cards?
Then you can have it running indoors on the dining table 




Ralph.

[sbwhart]

Now, Did you see that rolling rail for the loco? .... How cool was that!? When you get far enough one of them must be on the cards?
Then you can have it running indoors on the dining table 

Ralph.

Yep:- got the bearings safely stashed away for when they are required, also some garage door material for the cradle.   

Stew