Building a Boiler for a 3 1/2" Gauge Locomotive

[NickG]

Stew, great work there - I wish this (boiler) was one of those projects where you made 2 of everything 

  I was at our club last night with my oldest son as they had a running night / bbq and a guy offered me a drive of his 3 1/2" gauge william engine. I was surprised how much power it had, he'd already been around the track a good few times, I got on and managed to lose most of the pressure (out of practice!) but it was still pulling me up the hill on 25 psi!

That has the same cylinder bore as mabel but a smaller and 2 more driving wheels and a slightly bigger boiler. Still, I think Mabel should have a decent amount of power and once up to speed the bigger driving wheels might make it a bit more efficient, it'll need to be because of its smaller boiler though. Should be good.

Your post is inspiring me to get mine done, watching  / driving them helps too.

Keep up the good work.

Nick

[sbwhart]

Thanks Dean:- Solder sticks are 20" long

Tushie has cooled down now

Cheers Nick, I must say I've enjoyed my visits to the club track to see the boiler inspector there is always some one there running a loco last weekend was an open weekend for other clubs to visit and run their locos, there were some amazing machines buzzing round, the 2 1/2" gauge locos are just incredible tiny little things pulling a couple of grown men around, and all with drivers with huge grins on their faces.

This soldering is getting to be routine with Johns help and guidance soldered the rest of the stays as for the crown stays we put a ring of solder in the water cavity and a ring on the head of the rivets positioned the boiler with the end of the rivets sticking down applied heat to the ends with the big torch and used the little torch for background heat and to locally boost heat where required, all went well, just a couple of stays needed a second heating and a bit more solder applying on the outside the inside (fire box) all soldered well.

Here a few pics







Taking it along to the inspector this Sunday whilst there I'll buy yet more solder.

Stew

[shoey51]

thats coming along nicely Stew
wont be long and you will be one of the men with big grins

[Stilldrillin]

Graham,

If I`d produced something like that....... I`d have a blummin big grin, already! 

Nicely done Stew! Good luck with the Inspector.....  

David D

[Bluechip]

Stew

Ooh Aarr, Proper Job be thaat .. me luvverrr

Sorry Stew, old mate from Cornwall just been on phone ..

Coming on well.

Just been through the thread, just what Loco is it. ?? Sure you've told me, but I've fergotted ..

Dave BC

[Rob.Wilson]

Hi Stew
  lookin great, very tidy soldering   

Regards Rob

[Divided he ad]

That's a mighty fine copper hedgehog there Stew 






Looks absolutely solid! Should be a sure thing for the inspection..... Bet you can't wait to get into the pressure testing stages?



    I got a whole hour in my 'shop today.... Repaired my dads remote car key, my nephews scooter and did a little on my rocking engine (very little)....  Oh to be retired and able   






Glad to see your having fun 




Ralph.

[Brass_Machine]

Wow Stew that is coming together very very well!  Good job sir! 

Eric

[Dean W]

You've sure done a good deal of hard soldering Stew.  Bet you've about doubled the value of the boiler by now!
What good experience you're getting.  It's a good one for all of us watching and reading, too.

Great stuff, as always!

Dean

[sbwhart]

Bin away for a few days with my 85 year old Dad just to give him a bit of a holiday did him a world of good. 

Soldered the fire box back plate in place, couldn't get hold of John at short notice so press ganged my wife onto the job, she was a bit wary of the roaring gas torch at first, but she soon got the idea and carried out instruction faultlessly with no arguments, which for a strong minded woman must have bin very difficult.

This is the result





Started to mark the back head out for the fire hole and ran into a problem, The drawing for the fire box back plate is wrong it doesn't match up with the position shown an the back head, it positions it too high, I'm stuck with what is a wrong part assembled to the boiler, at the moment the fire door will foul the water gauge, 

It looks like I'll have to juggle thing around to get things to fit, still thinking the problem through.

Stew

[Rob.Wilson]

OUCH Stew    ,, hope you fined a way around the problem .


Rob

[DMIOM]

..........It looks like I'll have to juggle thing around to get things to fit, still thinking the problem through.....

Stew,

you're obviously a tactful man and/or one who thinks beyond the short term - a lesser man might have blamed it on his new assistant! 

anyway, have every confidence you'll sort it - either re-design it better, or given you're up-to-speed, just knock another one up in a few hours!

Dave

[sbwhart]

Nocked up a fire door this morning so I could 3D the problem 



Spent a bit of time down the club talking the option over with the guys, the best option would be to have the hinges at the bottom of the door, apparently on small gauge engines this arrangement is easy for driving, also did a bit of on line searching and found an engine the same as mine with the door hinged from the bottom it looks like the builder came across the same problem as me. Just to make sure I'm going to make the bottom end of the water gauge and the feed clacks so that I can check they won't foul the door, if they do only option will be to make a new back head and position the clacks under the door.

Stew

[Stilldrillin]

Don`t fully understand yer problem Stew...... 

BUT, I`m quite confident you`ll sort it! 

Bottom hinged? Hmmmm..... That`s lateral thinking! 

As Dave Lee Travis used to say. "Think literally. Think laterally"..... It works! 

David D

[Dean W]

Sorry to hear about this problem, Stew.  At least it's not a fault with your own work!
Hinging the door toward the bottom looks like it makes perfect sense.  I hope it works
for you without other obstacles. 
Thanks for the updates.  This is a great build thread!

Dean

[sbwhart]

Thanks Guys

Made enough of the fitting so i could try the fit out, for those interested this is how to fabricate small boiler fitting up, this is for the clacks.

First turn up the parts drill a cross hole in the body 3mm, on the union leave a small boss  3.05 mm dia and drill a pilot hole in the other end part way through, press the boss into the body and solder the bits together.

These are the bits



Bits prepped for soldering parts fluxed and a small nugget of solder put on the joint.



When you solder the bits together don't direct the flame on the job you'll just blow the nugget off sneak up on it with the heat when the flux will go white then black then it melts when it melts it will hold the nugget in place give it more direct heat untill you see the nugget melt and flow into the joint, pickle, then drill through the pilot hole into the body, thats it job done



Now this shows the problem with the fitting in the boiler the door fowls them.





I arnt half glad I made the the fitting as anothe problem materialised, you can't fully screw the bits into the back head they clash with each other.



I'm going to make a new back head but I'll leave that till next week as I'm starting to get pissed off with it and when that happens I make mistakes.

I may have said before that this was the last engine Curly designed before he passed away the drawing and ME article was finished off by Martin Evans and apparently the two didn't get on, the boiler fitttings are Martins designs they are obviously not what Curly intendes I wonder how many other builders have fallen at the hurdle.

Cheers

Stew

[NickG]

Good idea Stew, it is annoying that though. I am sure your layout of backhead will be far neater anyway, it's all a bit tight.

Will have a look at mine again tonight I think. I think, my water gauge doesn't have a blowdown, which is a requirement now anyway and would fail a steam test I think.

Nick

[shoey51]

Stew are the clacks for the water topup as I would have thought that they would have been fitted to the side of the boiler. as it is shown there it would make a very busy footplate area
nice work tho mate

[sbwhart]

Thanks for the PM Nick with the pic showing your back head.

Graham

Yes the clacks are for water top up, there is one in a forward position into the boiler from the axle pump, of the two on the back head, one is for the tender hand pump the other is for an injector, the UK boiler requirements is for two independent water feed systems so I guess I could do without one of them, the jury is out on which is the best system some people say that the axle pump takes too much energy out of the system so get rid of that, others say that injectors are too temprimental so get rid of that, but all agree the hand pump is a must.

Stew

[shoey51]

Thanks for that Stew Its prety much the same here. I personaly would have put a clack on each side of the boiler at the front just before the smoke box. and as is done on my loco use NRV and have dual inputs to each clack.and left the firebox area a bit clearer. but as you say you were following the plans and we learn from hindsight.
great work anyway mate
cheers Graham

[NickG]

Stew, no problem.

I my boiler doesn't have the clack on the side the feed pump pumps to the back right hand clack. The bore of the pump is so small on this engine I don't think it'll take that much energy out of the system. For every reliable injector i've seen i've probably seen 2 unreliable ones but they are nice when they work! The hand pump is a good fail safe, I was going to say I think our club insist on them, but that can't be right because you don't see them on the larger scale models like traction engines.

Nick

[sbwhart]

Over the last couple of days I've made the Turret or Manifold to none steam people.

But first to finish off the clacks, the balls need setting down to do this take a new 3/16 stainless ball bearing put it on the seating, and with a brass drift give it a sharp biff with a light hammer, throw the ball away as you've distorted it, replace it with a new one. Now make the cap first measure the depth to the ball and calculate the length of thread required to allow the ball to lift 1/32 ".

Here we are one done No two measured for the cap.



Now for the turret this is made from phos bronze I've bin using calphos which is a leaded bronze that machine very nicely. The body of the turret is made from a length of 3/8" dia material:- drill 1/8 27mm deep and drill and tap 3/16 * 40 ME 5mm deep the body uses a 1/8 steal ball valve for the whistle so the bottom of the 1/8 hole needs to be square and accurately depthed, so I made a flat bottom drill and set it to depth to the chuck face against a steel washer, and just kissed the bottom to bring it to the correct depth.



3/32 hole drilled right through the bottom for the plunger.

Keeping the job on the bar transfer to the mill in spin indexer, and drill the cross holes 3.5mm to locate the fitting for soldering.



Back onto the lathe part off to length flip it round and drill and tap the back end 3/16 * 40 ME

The fitting as there were 4 to make 1/4 * 40 turn up a length of bar enough to make all four and thread it with a die.





The turn up a 2mm long boss for a tight fit on 3.5mm hole drilled in the body part off



repeat repeat repeat.

Then flip them round in a collet:- face centre drill and drill a 3mm hole part way through.



Turn up the other 5/16 fitting

Here they are assembled to the body.



And fluxed with a little nugget of silver solder waiting for some heat.



Again sneak up on it with the heat the flux will go white then black then it will melt more direct heat until the solder melts, pickle for 1/2 hr.

Then set up in the mill and with the aid of the 3mm pilot holes drill through into the body. If you stick a bit of wire down the hole you'll feel/see the drill start to tickle it when it breaks through.



Set the ball down on the  seating as for the clacks.



Then make the whistle lever thing sorry this is the only pic I took.



And her we are turret finished.



With the bits made I can now see the best way to fit them on the back head, I think I'm going to black the bush up on the left next to the water gauge and move the boiler feed clack to the top right hand side.

Like this



Cheers

Stew

[Bernd]

Lookin' real good there Stew. I like that Manifold. Nice job. 

Bernd

[Rob.Wilson]

Hi Stew
  great job making the manifold  ,,,,,,,,,,,,,,,,,,,,,, whats that i see on the end of your vernier ?  did you make it  ? 

Rob

The fire hole door looks like it should be that way 

[Stilldrillin]

Very nice work, (again), and problems very nicely sorted, Stew! 

David D