A small boiler

[firebird]

Hi

This follows on from a topic I started in the " QUESTIONS AND ANSWERS" section entitled "WHAT IS IT" that is currently on page 1 of that section but will move down as time goes on. For those that have just joined in go and take a look at where we are to date to save me the trouble of uploading it again. As a relative newbie to this hobbie this is my first attempt at boiler making so must be considered as experimental and not a set of plans to follow. I'll try to show as many of the mistakes as possible so others may learn from them. (Perhaps mistakes is the wrong word, the path along a steep learning curve may be better). I have decided to make the 'PORKY' style of boiler as I think that will be within my current skill level. Due to work/domestic duties/wife/children etc this project may take a while to complete so bear with me as I often go weeks in between visits to my shop. Anyway I'm going over to photo bucket now to upload some photos, see you all in a while.

Cheers

 

[firebird]

Hi

Well here we go.

I started by cutting off the other end of the tube and checked the wall thickness at bothe ends and around the circumference and found it to be uniform. I then took some accurate measurements of the internal diametre. To make the end plates I had already decided to make a die and punch and press them into shape. Starting with a couple of pieces of scrap oak approx 6" X 5" x 1 1/2" I marked 2 of the edges to make sure they always go together the same way.

With the two pieces clamped together the centre was marked and the four corners approx 1" in from the sides and drilled right through both pieces with a 1/8" drill while clamped together. The centre hole is for linig up in the lathe

The four corner holes are drilled out to 8mm (sorry about the jump from imperial to metric but I use whatever I have to hand) and counterbored in the bottom of the die to take coach bolts with the threads cut off. These will act as four guides to keep the die and punch in alignment. Two holes were drilled in the base to aid removal.

The die was then mounted on the face plate using a tailstock centre in the centre hole and bolted on using 2 of the corner holes.

A tool was ground up from an old wood chisel to give an internal and external 1/8" radius and mounted at centre height in the tool post.

The die was then machined out taking care to get the diametre exactly right. The shape of tool giving a radius to the corners.

A shallow recess was machined to accurately locate the copper discs. (Shown in later photos)

The punch was first centred on the face plate and bolted on then the face plate removed and the die screwed on to the face plate.

Using the same tool the punch was now turned once again making sure that the diametre is accurate. The copper plate I'm using for the end plates is .080 thick so the punch must be .160 less than the diametre of die. The shape of the tool gives amatching radius on the corner.

A smaller block of oak approx 3 1/8" square was screwed to the face plate and a piece of the .080" copper plate held on to it with double sided sticky tape. Another piece of oak approx 1 1/4" square with its corners rounde off and centred was used with a revolving centre in the tailstock to apply pressure to the copper plate. The copper discs were then turned to size

For coach bolts with the threads cut off were then pressed into the die.

The job moved to where I work cos thats where we have the press. The copper disc was fistly annealed.

Then the disc was placed into the recess in the die and with a few packing pieces was put in the press

Not a great success. Because I had made the die and punch to exact size of the finished end plates it didn't press very well. What I got was a shallow dish.

Back to the drawing board. Both die and punch were remounted on the face plate and made much deeper so that the copper disc would be pushed right down inside.

Back at work on the press the disc was re annealed and pressed again. This time more successsfully.

Only problem here though I couldn't get the copper out of the die so had to cut a groove to get a screwdriver in to prise it out.

Copper slip grease was used inside the die and punch.

The second pressing resulted in a lip being formed where the cut out was so several re annealings and turning the disc around gave a pretty good end result.

Back home again and the discs remounted on the punch and cleaned up with a parting tool.

After a quick clean up and pickling they look OK.

Cheers

 

[BobWarfield]

Say, that's a neat project. Always wanted to fool with some die work.

Best,

BW

 

[Julian]

Hi All,

Just been round to share a beer and the work is excellent. Both fit well and look good..



Julian.

 

[Alphawolf45]

Thats awesome, I really mean that .

 

[firebird]

Hi

Thanks for the nice comments. A couple of things spring to mind. With the copper annealed it pressed very easily. I would think a good bench vice would do the same job. A loose fitting steel disc of say 1/8" thick in the bottom of the die would have made removal of the copper a lot easier. I have a few questions of my own to put to you guys, should I put them in the questions and answers section or carry on here?

Cheers

 

[BobWarfield]

If they're related, carry on by all means!

BW

 

[firebird]

Hi

I was going to have a go at making a water guage but at a recent show I bought one for £20.00 along with a small pressure guage.

The glass will need to be cut down a bit obviously.

I need to fit the water guage and provide bushes for the pressure guage, water injector and stays. I'm thinking of fitting two stays, phospher bronze.

Do these positions look right?
Will 1/4" dia. stays be ok.?
Whats the best way of fitting the stays?

Cheers

 

[DICKEYBIRD]

Great post firebird! Great pics and descriptions of the project.

I'm no tool & die man (or boilermaker either...I just drink 'em when I'm REALLY needin' to relax) but you'll need to make another form tool to get the correct radius on the male part of the die. The inner radius has to be smaller to compensate for the thickness of the material. Draw it out and you'll see what I mean. No criticism meant, just a suggestion.

 

[Bogstandard]

FB,

I wouldn't worry too much about radii, normally, when you make these, they are made by belting the edges over a male mould with a hammer, and cleaning up afterwards.
Yours will be perfect for the job. Well done.

For all your boiler needs, I would suggest sending Sandy a PM, and ask him to have a look at your post. He makes boilers for a living, and is honestly the best sort of boiler information man I have ever come across. He will let you know what sort of legal requirements are required for your end cap stays, and most probably suggest the best way to fit your sight glass (maybe at an angle, rather than vertical).
If you can't raise him from his deep sleep, I would suggest having a look at his horizontal boiler plans, and scale them up/down to give you the hole distance ratios and positions.

John

 

[firebird]

Hi John

Thanks, I'll give him a nudge now.

Cheers

 

[firebird]

Hi Dickeybird

Thats right the inner radius is smaller than the outer. Bit of a slip up there but John Bogstandard thinks I will be OK as is but its something to remember next time. Like i said I aim to show any mistakes I make and hope others will point out any they spot.

cheers

 

[DICKEYBIRD]

Right, your finished parts came out great and will work very well. I was just mentioning the differing radii issue in case you do some more. I think it would work better and the finished part may even release easier. Note I said may.

Please keep posting about this project. It's very interesting. ;D

 

[SandyC]

;D

Hi Guys,

Firebird, Sorry I missed your original post and questions, I have had lots of visitors (family etc) over the last couple of weeks (still got some to arrive) so have not had much time to view all the posts.

I must first say you have gone to a great deal of effort to produce the end plates for your boiler and they are looking very professional, well done.
I do mine the way John said.... hammer them over a former wiv a BIG ammer....he he.....I do use metal formers though.

Looking at the photo's, and some of the dimensions marked on the formers,  I have come to the conclusion that the main barrel is 3" OD is this correct?
I am not sure what working pressure you intend to use, however: -

I would suggest that you alter the stay spacing somewhat, and also to increase to 3 stays, in order to give the end plates a more even support....your proposed spacing would leave the centre of the end plates vulnerable to pressure (and therefore likely to bow out).
Your proposed bush layout would certainly work (the vertical water gauge is perfect), however, since you also do not show a steam outlet, I would suggest you add a steam dome (as per my horizontal boiler plans), this will make the end plate less cluttered (possibly aiding final boiler mounting), and with fewer soldered joints.

The stays need only be 3/16" dia (you may even be ok with 1/8" dia depending upon working pressure).

Suitable bush dimensions can also be found on the horizontal boiler plans (you may need to adjust the threads to suit your fittings) but the overall sizes would be common.

I also suggest that you mount a Safety valve in a separate bush located on the top of the barrel at tha opposite end to your steam outlet.

The size and pitch of the conduction stubs is not all that critical, however, there is no advantage to having more than 3/8" extending inside the barrel and 3/8" - 1/2" projecting towards the burner will be more than sufficient.

What I will say is....only fit them over an area much the same as your burner (you have not said what you indend to use for this, but I assume some sort of ceramic type), any more will just be wasted work and materials and serve no useful purpose.

If using a ceramic burner, then make sure you keep a gap of (at the very least) 3/8" between the top of the burner and the end of the stubs, otherwise you may find the burner blows back (due to localised heat reflection) and burns benath the ceramic....not a good thing.

I attach a PDF of a suggested layout that would satisfy your needs and remain safe as far a stresses are concerned.
Hope it helps.

This type of boiler (I know these as HEDGEHOG boilers) is a good first build, being relatively simple (having no internal joints) and will certainly allow you to get the hang of silver soldering if you have never done it before......since even a duff joint can be relatively easily remade, whereas, with a centre flue type you would be hard put to repair a leaking internal tube joint....It can also be quite an efficient boiler for small engines.

When fitting the stays....solder the mushroom head end first, then turn the boiler over and solder the countersunk end.

Keep up the great work and ask away if you need anything else explained.

BTW where are you located?.....I guess the UK, since I spotted the MYFORD.....not to many of thse in the USA.

Best regards.

SandyC  ;D ;D


PS...John.... I never fall asleep on the job....I just don't wake up in the first place.... Ha Ha.
Thanks for the vote of confidence though.



View attachment Hedgehog boiler detail.pdf

 

[AllThumbs]

Drilling a hole in the back of the female part of the mold would have made it possible to push out the copper disk from the back.

Eric

 

[firebird]

Hi Sandy

WOW! Thats a load of info for this brain to take in all at once. I will be re reading that several times. Yes 3" diametre is correct. I had it in mind to make a steam dome for the outlet and safety valve but thats a ways down the road yet. One step at a time will do me. I thought a working pressure of 35 psi would be ample for a small engine (not built yet). I intend to make a meths burner as the heat source.
Yes I'm in the UK, in the midlands north of Leicester. Once again many thanks for the help. I'll be back.

Cheers

 

[firebird]

Hi Eric

There are a couple of 8mm holes I drilled in the die but the first pressing was so tight it wouldn't push out. If I had used the grease in the first place that would solved the problem. The second pressing came out easy.


Cheers

 

[firebird]

Hi

I had the day off today (extra day on the bank holiday) the wife went shopping so guess where I went. Today I decided to experiment with a meths burner for the boiler. I think in Q & A section I posted this photo of a burner I saw a guy using at a show and thought I would use the same Idea.

So heres how I got on. This is only an experiment but was good soldering practice.

A short piece of 22mm copper pipe was used. For this I needed 2 end plates. I decided to make a small punch and die, similar to the boiler, to flange 2 pieces of thin copper, .035" thick.

snip out 2 pieces of copper

File round

Make a punch and die on the lathe in steel. Anneal the copper and press them in the vice

Make a stand out of copper

Make 2 brass bushes threaded 5/16 X 32. Make a brass filler plug. Make a brass tube drilled 1/4" and thread one end 5/16" X 32. Make (for lack of better words) a small brass cup. Make a top for the cup a nice push fit and drill six holes (jets) 1mm. Solder it all together.

The first trial didn't go to well. It wouldn't light, so I increased the jet size to 2mm. In the end I used the propane torch to light it! How many eagle eyes have spotted there are in fact only 5 holes. I broke a drill in the last one!

Once it was going it was ok but not brilliant. I figured the brass top has to get hot to vapourise the meths and maybe it was to thick and would not heat up sufficiently so I made a new top from the thin copper sheet.

This worked better but was still difficult to light.

I lit it without the top on. Lit easily and seemed to give a better flame.

Finally I made just a straight tube with a wick and lit it. This seemed to give the best flame of all!

It looks like I will stick to 3 or 4 simple wicks in the final burner.

Cheers

 

[firebird]

Hi Sandy

Just looked at the PDF you posted for me re boiler end plates. What can I say. Brilliant.

Many thanks

Cheers

 

[CrewCab]

FB ;D ......... this thread is brilliant, I'm on information overload ........ and trying to store it away for future use ........... the information you've provided so far is excellent and I've already learnt lots, please keep updating as and when you can .............. Thanks to all


Dave