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

[sbwhart]

Hi Chaps

I've been putting this off long enough.

But first a warning:- boilers are pressure vessel and are dangerous they are not to be taken lightly, if they fail they can cause serious injury, so due care needs to be taken when you build one. Make sure you understand the boiler regulations that apply to your part of the world, and if you have no experience of boiler building, find someone who is that can guide and mentor you.

I did a lot of research on boiler building, to some extent this was a mistake as I found a lot of contradiction in design and methods, to such an extent that I was seriously looking into buying a commercially made boiler, but this would have cost up to £1500, but I began to realise that methods and thinking have changes over the years and talking to club members and the clubs boiler inspector cleared a lot of the uncertainty up, and with encouragement I decided to have a go at building my own.

To help you Guys to understand some of the term used in the UK I've done a Crap-O-Cad of the type of boiler I will be making.



By way of explanation of some of the terms:-

Stays:- addition support given to flat services

Supper Heater Tubes:- these are large tubes through which pipe work runs that takes "wet steam" collected in the steam dome back through fire box to give it an extra dose of heat.

Throat Plate:- front part of the outer fire box

Foundation Ring:- This fills the space between the outer and inner fire box

Front and Fire box Tube plate:- These are the plates that the Flue and Superheater tubes fit too.

I think the rest of the bits are self explanatory.

I bought a boiler kit for my Loco from Reeves it cost £290.

This is the kit of parts.



Everyone I've spoken to has given me the same bit of advise:- the key to good boiler making is in the preparation, so over the next week or two I'm going to spend some preparing for the build.

The adventure begins

Stew

[shoey51]

I for one will be watching this build 

[Stilldrillin]

Yer a much braver man than me Stew!

Good on yer! 

Hats off to you...... Good luck! 

David D

[lordedmond]

sbwhart

1 make sure you have enough heat   42 mm burner or bigger
2 Check and triple check the drawings for foul up's I did a Doris and the drawing had the hole for the regulator shaft lower than the fire box wrapper 
3 you can use citric acid as a pickle best to use a tall square plastic wast bin

above all listen to your boiler inspector  and don't forget to show him/her each stage of progress , take some pic to show the solder penetration as you go


Loco's to date Doris 3 1/2"  didcot 14xx 5"  Br class 2 tender 5"   and under construction a BR class 4 tank to D Hewsons plans been at it for two years and have just about done the chassis

BTW the 14xx and the class 4 tank are both fully scale with the 14xx having about 4000 1/32 rivets in the plate work ( done properly not stuck it )

I used to do my own boilers up to the doris fiasco now I get them built Class 4 cost upward of £2.5 k
Stuart

[sbwhart]

Hi Stuart

Welcome aboard the cube 

Thanks for the information/advice as this is the first loco boiler Ive built I need all the advice I can get.

4000 rivets  you wouldn't have a pic of that would you ?

 

Feel free to post it her or start your own thread.

Thanks again

Stew

[lordedmond]

not at this time as the cab roof is off for maint to the steam fountain

the bunker is done with backing straps for the plate as per full size

[sbwhart]

OK Made a start not to exciting but every journey begins and ends with a step.

You may think I'm sad but I like to plan out jobs as best I can before I start, I use to make my living designing building and testing items that could be a bit hazardous, if you didn't get your preparation right:- I just can't get out of the habit.

So after much reading and talking to people and listening to advice, I made out a list of items I thought I may need I may end up not using everything but its better to be prepared than wanting. I started my To Do List I'll add to this as thing progress, and as putting a boiler together is complicated and the order of assembly is important:- I listed the order I would assemble the boiler, I may combine some of the operations or even change things round a bit as they go but the shear act of making the list helps make things clearer in your mind:- its all part of the learning curve.

Her's the lists



The first job I thought I would tackle was to make some clamps I want to leave them outside to go rusty so that the solder wont stick to them to easy so the sooner I get them made the better.

A rummage through the scrap box turned these bits of material up.



I burn the paint off the long bars and just squared the ends and sides up in the mill and drilled and tapped them as for toolmakers clamps, they will get a bit of heat so nothing too posh, as long as they will do the job.

The shorter bars again were squared up and a slot milled across and the end drilled and tapped M5, I rounded the jaws off in two of these so that I could grip the rim of the tube without the sharp edges damaging the soft copper.



I was going to make a pair of tongs but them I remembered these.



I bought them at a car boot sale many years ago, don't know why I just thought they would be handy one day, well their day has arrived  ;D

Cheers

Stew

[Stilldrillin]

Stew,

That posting is completely about how you do your forward planning........

Starting, long ago, with the tongs! 

Nice one! 

David D

[madjackghengis]

Hi Stew, I'm really looking forward to this build, I've put off building a few steam engines because I was leary about building a boiler, yet didn't want to just build an "air" engine, and run it off of the compressor.  I expect to follow this one very closely, and see if there is anything keeping me from going ahead, and building one, and finishing up a steam engine, long ago started, but just barely, and definitely calling out in desparation.  The price of the kit sound's high, but from the look of it, you got what you paid for, the parts are good looking and substantial, and ought to end up making the build fairly straight forward.  Good luck and take lots of pictures, a lot of us are counting on you!!! mad jack

[sbwhart]

Thanks Dave and Jack

Jack like you I've been very wary about building a boiler but short of making an electric loco you can't avoid it, the guys at the club are real keen on people building their own they've all done it so they see no reason why any one can, but I still feel nervous about it, not as much now that I've started.

Any way bit more progress I checked the kit of part out and to be honest the flanging is very rough, they look like a Gorilla with a sledge hammer went to work on them. The fire box tube plate should fit in the boiler tube:- No way its about 3mm big



So decided to make a set of former plates and do the job myself, for one off use you can make formers from hardwood or MDF, but the last time I used hard wood I ended up with an allergic rash that took a month to clear up, so nothing for is I'll just have to use ally jog plate a lot more hard work, but one thing old Stewpot is not afraid of is hard work, so after 1 1/2 hr a sore arm, and a bucket of sweat, I got them rough cut out of the plate.



The smoke box tube plate former is round so, the rough cut plate was set up for friction turning.





Before taking an hammer to the copper I annealed it by taking it to a red heat and quenching it in water, this gave me a good feal for the size of burner I'll have to use when I come to solder I ended up using my next to largest burner.



The build guide recommends allowing 3/64 for the plate thinning under the hammer but I gradually reduced the dia of the former trying the tube plate in the tube taking a bit more of the former bashing the plate and tryinng it in the tube until I got a nice push fit.





Next job the fire box former, this is a job for the mill.

I squared the plate up then dolloped some blue on the plate then I used a centre and the DRO feature on the mill and a set of compasses to mark out the shape of the former and and hole positions I then centre popped all round the line.



Back on the mill to mill the shape out you could use the RT for the Radiuses but that level of accuracy is not required I used a trusty old file to bring the shape to the scribed line.



Her's the former and the tidied up fire box plates.



Cheers

Stew

[Darren]

Very nice Stew, I found that quite informative 

[Stilldrillin]

Nice work, Stew! 

David.

[shoey51]

wow Im impressed with this build and Im learning as I go
great work mate

[Dean W]

Good work on this, Stew.  I always like your build threads.

Dean

[lordedmond]

that burner will not be big enough to SS the boiler

if you use that one you will need another for the actual SS work use that one to pre/hold the main heat

do not make the joints to tight the SS needs room to flow into and though the joint , under no circumstances rivet the joints up tight

[sbwhart]

Thanks for your comments chaps

And thanks for the advice and input lordedmond,

I have a second burner to add more heat but have yet to get a second propane tank.

Cheers

Stew

[madjackghengis]

Nice work Stew, beware the man with more than one hammer, he may know how to use them!  I have much respect for a man who can use a hammer, and end up with a good looking, well fitting part, not covered in hammer marks.  All that work on the tube plate along with the pristine fire box plates will look beautiful when it is soldered together.  Great start on the boiler mad jack

[Brass_Machine]

Great start on the boiler Stew. One of the things holding me back is making the end plates. Looks like you got through it pretty good. Maybe this winter I will give it a try. Hopefully mine will turn out at least half as nice as yours. 

Eric

[Buddpig]

I have a 3d solid model of an 1 1/2 scale 0 6 0 boiler, its almost completed, few more things to do, if you are interested I can Email it to you, It would not let me attach it on here, when I zipped it then opened it back up with a dxf import , it was not a solid model anymore.

Cheers

[sbwhart]

Thing have been a little slow, bin on Gardening Duties and looking after our grand son.

Any way made some progress with a backward step thrown in, more about this later.

Made the former for the backhead plate you this former for the throat plate as well. First square it up so that you've got four good edges on each face, then blue it up and mark it out on the mill.



Then centre pop the line to give you something to work too.



Then mill out the shape I used the rotory table this time, it just fitted the clamping is not too elligant, but hay:- its effective.



Then it was just a matter of tidying up the plates on the former her they are all done with the formers.



Now to drill the tube plates now I know that "drilling soft copper can be tricky",  I've seen lots of pics where guys have mounted tubes plates onto lathe face plates so that the holes can be bored because "drilling soft copper can be tricky" but for some reason I decided to do the drilling on my pillar drill, its not a bad pillar drill but its not as good as my mill for drilling, I clamped the smoke box tube plate onto a plank of wood and drilled the first 3/8" hole all was well, now I know that "drilling soft copper can me tricky", second ran out nearly into the first hole that I drilled, I stopped and tried rectifying it by drilling from the other side but this only made things worse:- strike one tube plate



OK it's a scrapper:- so decided to drill the rest of the holes any way to perfect the best method.

Over too the mill:- this is the set up, the plate was position over a slot for the drill to run into and clamping onto a chunk of wood in the middle, so the flange wouldn't be damaged.



That worked like a dream why didn't I do that to begin with 

OK have a go with the 3/4" supper heater holes now I know that "drilling soft copper can me tricky",    so similar set up, but this time I sat the plate on some parallels flat side on, as the 3/4" was to wide to fit between a slot,:-a 3/8" pilot drill then straight in with the 3/4" now I know that "drilling soft copper can me tricky",  that one wandered off centre as well I should have used another pilot drill.

OK second 3/4" hole this time 3/8" followed by 1/2" followed by 3/4" perfect

This is the scrap plate, the 3/4" hole on the left is the one that run out. you can work out for your selves which 3/8" hole went wrong.




Guess what I'll be buying at the Harrogate show, still I've got the formers know.

Stew

Who knows that "drilling soft copper can me tricky" 

[P.J]

Stew

Who knows that "drilling soft copper can me tricky"  

Not sure it's possible given the shape of the plate you'r drilling... But you can try
clamping the copper plate between two thicker pieces (1/4") of aluminium and drilling through all 3.
This usualy results in a perfectly round hole with nice crisp edges when working with soft or thin materials.. allthough marking out and making sure the hole ends up where it's ment can be a bit of a pain..

Maybe it's possible to turn a 1/4 plate with an OD fitting the ID of the copper cap, mark out on the alu plate and clamp the whole contraption to a second alu plate, drill the holes and Bobs your uncle?

Keep up the good work  

/PJ

[shoey51]

Hard luck there Stew but I think you have it sorted now.
soft copper has always been a pain to drill.

keep up the great work mate

[Artie]

G'day Stew, this thread is particularly of interest to me because Im gearing up to do the same for my build. Im at the stage where I need the boiler soon as its the mount for the cylinders and crossheads. Im watching with interest 

I like your attention to detail, its going to pay off in the end, it always does. I dont know what your silver soldering skils are like but if you havent dont much the ruined plate could be a bonus. I would get some scrap tube and practise on it before you attack the real thing... it can be a bit tricky at times.

I am of the opinion "drilling soft copper can me tricky"  , the method mentioned by PJ is a sure one. Youve already got the formers why not drill them and use them as drilling guides? You just need another piece to go behind them (simple flat square) these wont need to be drilled......

Also, if you can repair and resize the end plate, I think you can make a new one from scratch... seeing what you have done to date...I have faith in your abilities....

I cant believe how much the kit cost, amazing, talk pressure vessel and you start adding zero's to the end of a normal price range... ridiculous...

Looking good.

Cheers

Rob T

[Rob.Wilson]

Hi Stew 

Very interesting build    ,,,,,,,,copper can be a real pian to drill    i have posted the way i drill copper and other sheet material on another thread as i did not want to spoil yours http://madmodder.net/index.php?topic=3042.msg32719#new
Keep up the great work

Cheers Rob

[sbwhart]

Thanks for your tips and input guys between us we will get this job done. 

Thanks Rob

I picked your drill thread up, I'm going to have a practice grinding some drills like that, my Dad was the charge hand in a little shop that refurbished tooling for a large production shop, he use to grind drills up like that all the time, he's still with us but no longer has the faculties to show me how to do it.

We're going over to Buxton today with a diversion to maccmodels https://www.maccmodels.co.uk/ so that I can pic up some copper sheet, my Boss doesn't know it yet  

Thanks again

Stew