Part built Allchin 1.5 inch

[derek blakeParticipant @derekblake72550]

I think once the engine is built if I ever see my boiler I will keep it looked after and oiled up.

so I will make the piston from SA660 bronze as that's what I have at home, I cant see that being a huge issue from what I've read from everyone.

The original should be GM or bronze and piston bronze, only thing is the piston maybe a different type of bronze but the drawings don't say,,,

Regards,

Del

[Ian S CParticipant @iansc]

I think that rather than cast iron in the bronze cylinder, stainless steel might be better to reduce the effect of corrosion. Even if the engine was only run on compressed air, cast iron would be at risk of rusting because of the moisture in the air, and condensation on the cold cylinder. O-ring or Teflon tape seal in a polished bore, cast iron ring in a honed bore to retain oil in the fine scratches formed by the hone.

Ian S C

[derek blakeParticipant @derekblake72550]

Hi Ian

How do you think a SA660 bronze piston in a SA660 bronze liner would cope?

[derek blakeParticipant @derekblake72550]

Hi

Just a couple of cylinder pictures today, clean up and drilling’s so far going well thanks to everyone’s help.

Pleased considering I have no milling machine

.

[Brian HParticipant @brianh50089]

That's looking very good Derek, well done!

Brian

[derek blakeParticipant @derekblake72550]

Thank you Brian

[derek blakeParticipant @derekblake72550]

Happy weekend all.

So I’ve had a go at the piston, please bare in mind I’ve never done any of this before so if you see an obvious mess up I won’t take offence if you tell me.

Piston is a sliding fit in liner and with O ring fitted I can hear a suction noise so I’m hoping I’ve made it correct.

[derek blakeParticipant @derekblake72550]

[Paul KempParticipant @paulkemp46892]

Derek,

Sounds about right. Couple of off the cuff comments; previously when making pistons I have roughed out the blank including the centre hole / fixing arrangements and ring grooves and then mounted the piston on its rod and held the rod true in a collet or clocked in the four jaw and finish turn the details to make sure everything is concentric and square with the rod. Good test is mount the piston on its rod, put your hand over the end of the liner, pull the rod / piston and release, the piston should return to the initial position or thereabouts if there is no or minimal leakage.

Paul.

[derek blakeParticipant @derekblake72550]

Hi Paul

Thank you for your comments, I’m pretty sure I’m all square but I do need to attach every when I get a 5ba tap to attach rod.

If I’m wrong at least I know what I’m doing next time, when rod is threaded on I will try the suction test to see if fitted well.

Many thanks Derek

[derek blakeParticipant @derekblake72550]

Slide valve and buckle hand filed, 5 hours work but not 100% sure I won’t need to start with a new one as there is a tiny amount of twist if you rotate the two pieces when together.

[derek blakeParticipant @derekblake72550]

[derek blakeParticipant @derekblake72550]

Hi All

So I've heard about my boiler and looks like it will be looked at in due course.

I have a question please, I have a boiler kit for the Allchin which I brought second hand, if this is made by a boiler maker I'm told that this can't be certified due to not having C of C for the copper.

this to me means that if I built the boiler myself and did a hydraulic test id save myself £2200 which was quoted.

this isn't something I will take up, but the point I'm making is for all boiler made in the home environment do the builder all get certification when they order the copper?

And if you build the boiler at home can you still get it certified to be able to use in public, its unlikely id ever want to do that but I'm guessing as the boiler has no build pictures or materials certificates id never get insurance.

I know this is a can of worms, but id imagine not many people build there own boilers for these obvious reasons.

Regards,

Del

[Brian HParticipant @brianh50089]

The easiest way to get a boiler tested and certificated is through a model engineering society or club.Most will not ask for material certificates if the boiler is obviously copper and if gunetal or phosphor bronze has been used for the bushes, all silver soldered. And, of course it helps that it is an established design.

The way to approach this would be to join a club and discuss the boiler with their boiler inspector.

Brian

[Paul KempParticipant @paulkemp46892]

Derek,

I don't think if you buy a kit of materials from one of the established suppliers to put together yourself it will be supplied with certificates. That said I have not bought a boiler kit since 2002 so may be wrong. Anyone else bought one that can confirm?

The issue with the commercial boiler maker using your uncertificated material is I assume because they will have to CE mark the finished product so traceability of materials will be required.

As Brian said it is unusual for an MES boiler tester to ask for material certificates for copper boilers, they could do though if they were fastidious! Things are different for steel. You could get your home built boiler certificated by an MES but they would likely want to see the boiler during construction. It would also as stated have to be built in accordance with the published design (although they could accept a design of your own accompanied by design calculations if they are competent / confident to verify them). You would also have to be a member.

There are met labs I am sure that can analyse and test the copper you have if there is enough of it in excess of what you need to make some test pieces. The certificates they issue should be acceptable to your boiler maker. Might cost you what the material is worth though!

Why not have a go at building it yourself? If you do as Brian says and join a club you might even find some members will help you with the soldering.

Paul.

[derek blakeParticipant @derekblake72550]

Many thanks for both your comments, it’s an interesting topic I think.

Considering the limited boiler makers it also opens the question if there is space to open a new business.

I shall see how my present boiler gets on during finishing before deciding on the next step.

Thanks all

[derek blakeParticipant @derekblake72550]

Abit more work done, couple of failed attempts but got there in the end.

Oil lubricator turned with files, saddle machined to shape by hand filing away the mass of material and finished to size by rubbing against boiler barrel with wet and dry glued on.

Has worked great from what I can see, no lathe to flycut so this was my way of working around the lack of machine.

5 hours work instead of 1 but got there in the end, I’m sure some will say I’m mad and it’s not the correct way which of course I agree but it’s the way I could do it.

[derek blakeParticipant @derekblake72550]

[derek blakeParticipant @derekblake72550]

[Paul KempParticipant @paulkemp46892]

Derek,

Well done. The only 'wrong way' to do something is the way that doesn't work! We all have to make compromises at some point even with a reasonably well equipped shop! The use of hand tools and hand fitting is much under rated!

Paul.

[derek blakeParticipant @derekblake72550]

Many thanks Paul, at least I can say I’ve put some hard work into this engine.

[derek blakeParticipant @derekblake72550]

Evening all.

Well I’ve gone from proud to feeling very sad and stupid, looks like I’ve ruined the cylinder after all the work.

I had to chain drill and Dremel and file steam ports as I have no milling machine, however in doing this it’s not as accurate as it should be and the middle two section is thinner than it should, the separating splines for a better work should be 3/32 but mine come in at 2mm each, add that to the undersized 1/4 hole and my valve when sat in the middle covers exhaust and leaves open the side ports by half way.

Looking at the drawing and what I can others have done this valve when central should cover exhaust and the side ports but only allow steam into the valve steam space.

The way mine is steam could get down the side ports as my valve hangs over them half way each, I feel abit sick and disappointed in myself today.

Only thing I can think of is to get someone to machine a slide valve in the future with a thinner exhaust space so that it will only cover exhaust port when central, but not sure even that a fix, one positive is the width of all three ports together is correct st 15.87mm this part is fine, but the two spacing being undersized has left less material for the valve to sit on when central.

 

Edited By derek blake on 30/01/2019 19:13:49

Edited By derek blake on 30/01/2019 19:21:32

[derek blakeParticipant @derekblake72550]

[derek blakeParticipant @derekblake72550]

[derek blakeParticipant @derekblake72550]

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