A small boiler

[Metal Mickey]

Excellent thread and I really like your photo's. Nearer the end than the beginning now eh

 

[firebird]

Hi

Yes the end is in sight but all those last little bits seem to take forever. I don't really like to mention this but Xmas is rapidly approaching and as it does I get less and less time in the workshop so the end stretches out. Its nice to see it taking final shape though.

Cheers

Rich.

 

[firebird]

Hi

Tonight I marked out the top plate and drilled 5 holes using the funnel base as a drilling guide. The holes have been drilled with a #37 drill which is the tapping size drill for 5BA. (The brass nuts I am using are 5BA).

The top plate moved to the mill and centred using a laser. The plate has been raised away from the mill table using old car wheel bearings as spacers.

The hole is then drilled using a step drill up to 24mm. The step drill went through the ally plate very easily.

An action shot.

The hole drilled.

Making some 5BA studs in the lathe.

The finished studs.

Tapping the top plate in the tapping stand.

The studs fitted.

And assembled with brass nuts and washers.

Cheers

Rich

 

[firebird]

Hi

The boiler case wasn't quite flat on its top and bottom edges so I mounted it in the mill and skimmed a few thou of both faces.

Sandy made a suggestion about a firehole door.

I do like your solution to the variable air vents, now you need to consider fitting a firehole door which will help them perform more accurately by ensuring that combustion air is drawn through them rather than via the firehole.
Something else to think about!!!.

Well.............................OK................ go on then.

I started on the doors by making the hinges first. While figuring out how to make the hinges it suddnely came to me why not use readily available brass door hinges.

Knock the pin out.

Screw the halves to a scrap of wood and chop off the bits in the bandsaw.

I had to make a little jig to hold them so I could machine them all to size.

Two pieces of 3 mm ally plate held together in the mill and machined to size.

Then held side by side in the mill. Wheel bearings used as spacers and drilled out with a step drill.

Drill 1/16 holes in the hinges and the doors.

And then rivet them to the doors.

I countersunk the holes on the back of the doors so the rivets would lie flush.

Mount the other half of the brass hinge in the mill and machine out.

Once they have been cut out all the hinge pin holes were drilled out to 3/32. I have some 3/32 stainless steel to use for the pins. Slide some 3/32 through the hinges and clamp the door and hinges in the mill and drill out to accept 5BA.

Make some 5BA pins from stainless steel.

The hinge pins are 3/32 stainless steel with a small 1/8 stainless steel cap pressed on one end.

The pins just push in from the top.

They need to be polished up now to finish them off

A bit of video.



Cheers

Rich

 

[Maryak]

Rich,

Great work and great innovation with the hinges.

I have learned many things following your thread about this boiler.

Thank you for your posts, keep em coming please.

Best Regards
Bob

 

[firebird]

Hi

Thanks Bob, I do have very occasional flashes of insperation. I often think to myself " Iv'e seen something like that somewhere" but can never remember where, then after many hours of machining I remember when its too late.

Tonight I drilled 2 holes, one for the steam dome and one for the relief valve in the boiler housing top plate. It took less than a minute to actually drill the holes but nearly half an hour to set it up. I must have checked and double checked about ten times before drilling. For some reason I had convinced myself I was wrong somewhere but couldn't see it. In the end I drew it out on a piece of paper and then cut the holes out with scissors to make sure. Old age and paranoia creeping in I guess. Any way I'm glad to say it all worked out.

Cheers

Rich

 

[Divided He ad]

Nice work Rich!

I haven't been on much recently, so it's nice to find a whole load of pictures to see how good your boiler is doing ;D

I really like the doors. (step drills rule!!! ) Very inovative with the hinges.

I like your way of fixing the hinges too, some of us (Me) would have probably used screws.... Lazy I suppose!

Not long now till it's in full working order it seems?

Good to see it all taking shape.



Ralph.

 

[firebird]

Hi

A bit more work on the boiler housing today. To secure the top plate to the main housing I have cut 2 strips of 3mm ally and welded them to the insides of housing. They have to get round the slides for the boiler mounting plate which meant milling a little out of them. I decided to weld them in first and then mill the cut out for the boiler mounting plate, much easier to hold one long piece while welding. I will make some 5mm stainless steel studs and fit them with stainless steel dome nuts which I already have. Now that the plates have been welded in the boiler has to be inserted from the bottom.

Milling out the plates.

Clamped to the housing.

Then welded in.

Followed by the other side.

Milling the slots to clear the boiler mounting plate slide.

Drilling six 5mm holes in the top plate.

How it looks so far.

Cheers

Rich

 

[firebird]

Hi

I'm getting towards the point where I will have to fit the boiler fittings, water guage, pressure guage etc. Looking at various boiler setups the pipe to the pressure guage goes down in a loop then back up again. Is this the way to do it?

Cheers


Rich

 

[max corrigan]

Hi

I'm getting towards the point where I will have to fit the boiler fittings, water guage, pressure guage etc. Looking at various boiler setups the pipe to the pressure guage goes down in a loop then back up again. Is this the way to do it?

Cheers
Rich, boiler housing looks great, regarding the "loop" my stuart boiler has such a thing like a "u" bend as you say they all seem to have one, not sure why though!
regards Max...............

Rich

 

[ksouers]

Simple, the "U" bend is to allow for expansion of the pipe as it warms up. The assumption is that the gauge is hard mounted, meaning it won't move. If it was just a straight pipe it would try to force the gauge off it's mounting as it expands from the heat. You will also often see a circular loop for the same purpose.

You may find that trick useful in other plumbing situations. It is used frequently in long runs that may force joints or mounting structures to break if pushed too much.

Kevin

 

[shred]

As I understand it the idea is to have some steam condense in there into water, so as not to subject the pressure gauge to continuous hot steam.

So sayeth Martin Evans in his Manual of Steam Locomotive Construction (what I have right handy for some reason) "[the pressure gauge] must be fitted to a U or syphon pipe to protect the internal mechanism from unnecessary heat"

 

[SandyC]

NAH!... looks like a load of rubbish........ the gap at the top of the doors is 5thou wider than the bottom and you have lost the damper bars.......... yer just can't get the staff these days... ;D ;D :big: :big:

Just kidding Rich.... super job, well done indead.

Yes you must use a U - tube or a loop tube between the boiler dome and the pressure gauge. (also known as a syphon).

The primary reason is, as Shred say's, to allow a water column to form (via condensation of water vapour/steam during the boiler warm up period) in the tube to buffer the pressure gauge from the direct heat of the steam, which could otherwise damage the internals of the gauge.
On the small types of gauges generally used for models the BORDON tube mechanism, inside the gauge, is soft soldered (silver solder is to stiff) and direct steam heat can, and will, damage this.

The second reason is, as Kevin has stated and would normally employ the full loop type of tube, to allow the tube to expand when used with a panel mounted (fixed) gauge without the gauge mounting being placed under stress.

I find a tube of around 3" - 4" x 1/8" OD copper is sufficient for pressure/temperature up to around 45psi.
The tube should be in free circulating air and should not be lagged/insulated.

Do you intend to paint the outside of the casing?

Looking forward to seeing the finished and running boiler.

Very best regards.

Sandy.

 

[firebird]

Hi

thanks for the answers gentlemen, that makes sense, I see now why it needs a loop. Sandy has asked if I will be painting the casing. I don't think I will Sandy. During all the ally welding considerable heat was applied to melt the weld from a propane torch. Much more heat than will be produced by the spirit burner. The casing hasn't discoloured or tarnished or suffered in any way so I will leave it as is for now. I have no idea what grade of ally plate it is, I picked it up as an offcut at a steam fair. I hope to get a bit more done this weekend so I will keep you all posted.

Cheers

Rich

 

[ChooChooMike]

I've always wondered about those loops on steam pressure gauges I see in locomotives. Now makes perfect sense ! Same thing with the syphon on small gauges like from PM Research.

http://www.pmresearchinc.com/store/home.php?cat=117

Learn something new everyday !!

 

[firebird]

Hi


Just two quick questions. Do the little pipe nipples have to be silver soldered on to the pipe or can they be soft soldered? secondly how do I mount the small pressure guage, there doesn't appear to be any way I can fix a bracket to it.?

cheers

Rich

 

[SandyC]

Hi Rich,

SILVER solder.... there is NO PLACE for soft solder where steam joints are concerned.

Counter bore the tube about 1/8" deep for the small stub on the nipple (a good close fit) and then keep the heat more on the copper tube (the small nipple stubs melt very easily if you direct the flame on them too much) and use small (0.5mm or 0.8mm) silver solder wire to make the joint. (Available from 'BLACKGATES ENGINEERING')
Make sure you have the fitting nut in place before you solder the stub.

If your gauge is of the 1/2" dia - 3/4" dia type then the syphon tube is quite stiff enough to support it, you don't need a bracket.

Having said this.... these gauges are available with a mounting flange if you prefer that type of mounting in which case you would be better to use a full loop type tube rather than a U-tube.

Keep up the good work.

Best regards.

Sandy.  ;D

 

[firebird]

Hi Sandy,

I thought silver solder would be the way but best to ask first. I have melted brass parts already ( see earlier posts re the hydraulic pump) so I am wary of that. I bought one of those small torches that is filled with cigarette lighter gas and have practised silver soldering small parts together with that. I already have the small guage so will do as you suggest and just mount it on the pipe.

cheers

Rich

 

[firebird]

Hi

Not much shop time this weekend due to the iminent arrival of a certain Mr. Clause but long enough to sort out the fixing for the top plate. Six studs were needed which I originally was going to fit with 4mm stainless steel dome nuts but it didn't look quite right. After a littlle thought I decided to turn some little stainless steel pillars that were cross drilled to accept 1/16 brass rod that would look like a hand rail. Because the studs can't be seen I used 4 mm stainless steel cap heads locked in place with a nut. They are long enough to give me about 3mm of thread to screw the pillars onto.

The cap heads and nuts.

Turning the pillars with a round form tool then parted off. The same form tool was used on the top of the pillars but I forgot to photograph that.

Screwed onto the studs

Alength of 1/16 brass brazing rod bent and pushed through the holes.

Cheers

Rich

 

[BobWarfield]

Ah, the railing is the icing on the Gingerbread house!

Love the doors too.

I somewhat wish for door handles on either door made of the same thing as your railing.

And as well, it would be cool if you had the option to take the burner in from the back side so that you could view the whole works from the front with the doors open.

Cheers,

BW