Countryman’s Steam – Boiler

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Countryman’s Steam – Boiler

This topic has 14 replies, 6 voices, and was last updated 4 March 2012 at 21:34 by Sub Mandrel.

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3 March 2012 at 09:05 #2738
JasonB
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@jasonb
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3 March 2012 at 09:05 #86345
JasonB
Moderator
@jasonb
Well its good to see this series has started again in issue 4425 but a shame all the editing has left a bit to be desired.

Firstly all the thicknesses of copper are given in fractional inches, OK for us experianced modelers but for the beginner it would have been better to use metric for the sheet material as gauge thicknesses have not been available for some time and sheet was rarely sold in fractions. And the tube for the barrel should be the gauge thickness not fractional as copper tube is not sold that way.

Secondly it suggests the use of Easyflo No2 Now the article may well have been written when this was available but surely it should have been corrected to a Cad free variety to save beginners searching around for things they can't get.

J

Edited By JasonB on 03/03/2012 09:07:04
3 March 2012 at 09:18 #86346
John Stevenson 1
Participant
@johnstevenson1
Why not give the punter a free boiler if they sign up to a 30 year subscription.

That way they wouldn't have to work anything out for them selves.

There are always going to be dificulties when using old designs but not insurmountable. I'm reminded of a post on a forum where a guy had made a rear tool holder for his lathe.

Someone cherped up do you have plans for this even though he had a different lathe.

Plans ??? The design is limited by about 3 or 4 dimensions that should easily be workable out, chances are his original design wouldn't work on that machine anyway.

true beginneers need help but it's no use swaddling them in cotton wool or you will always have babies.

John S.

Edited By John Stevenson on 03/03/2012 09:22:35
3 March 2012 at 10:34 #86351
David Clark 13
Participant
@davidclark13
Hi Jason

I am not a boiler designer.
I do not change boiler specifications as designed.
If the builder wishes to convert dimensions that is fine.
He blows himself up, that is his fault.
If he does not have the required silver solder, he should go
to his stockist and get an equivalent.

regards David
3 March 2012 at 11:06 #86357
JasonB
Moderator
@jasonb
"If the builder wishes to convert dimensions that is fine.
He blows himself up, that is his fault."

But on an article aimed at the beginner surely we should be steering them in the right direction.

As it stands this boiler cannot be made as drawn, any alteration will in effect make it a "new design" so I strongly suggest anyone who has been following this build take the drawing along to their boiler inspector and talk through the revised thicknesses before buying or cutting any metal.

Would it not have been simpler to put a note to the same effect into the text or at least say that metrc thicknesses will have to be bought and the buyer should always go up slightly rather than down a size even if that is closer to whats spec'd.

Its not a case of wishing to convert, its a necessity.

JS I quite agree that on an older design things will have to be updated but this was only drawn a few years ago and this is the first time published.

J
3 March 2012 at 12:17 #86363
JasonB
Moderator
@jasonb
Any chance of getting the designer to say what wall thickness the 12 No 7/16" tubes are or is it just another case of suck it and see if it blows up.

7/16" OD is available in 16, 18, 20& 22 gauge at least.

Position of the manifold for the water gauge is also missing for front/back location and its now prefered practice to have the water gauge on its own manifold, this one looks to share the pressure gauge.

Again any beginners thinking of building this speak with your inspector first, don't take pot luck

J
4 March 2012 at 11:47 #86450
Adam Gregory 1
Participant
@adamgregory1
Hi David

Now this series has started again do you think it will be in every other issue or will there be a long pause again as i'm really looking foward to making use of the wheels i made last year.

Adam
4 March 2012 at 12:56 #86456
David Clark 13
Participant
@davidclark13
Hi Adam

I hope to run it till it is done.

It takes a lot of editing and I have not had the time until now.

Not that I have the time now as we have to get four magazines out in the next three weeks and two days. It will depend on getting the drawings done by the illustrator.

regards David
4 March 2012 at 13:15 #86458
David Clark 13
Participant
@davidclark13
From author In reply to JasonB.

The 7/16in. tube should be 20 swg, standard thickness from your friendly model engineer's stockist.

Jason B should be assured that if too thin a wall section tube is fitted, the tube is likely to collapse inwards, in other words flatten. The pressure is on the outside in this case and copper is less strong in compression. This would not cause a catastrophic collapse and would most likely happen when the boiler is tested to twice boiler pressure. This is why boilers are tested to twice boiler pressure. Subsequent tests are to one and a half times boiler pressure.

In typesetting my hand written dimensions for publication, in the end section to the right of the drawing on page 364, the 11/16in. dimension to the first row of stays should be from the top of the foundation ring as shown in the door plate drawing to the left. Also the 1/4in. should be for the foundation ring only and not include the firebox wrapper plate.

The front to back location of the water gauge bush and manifold will be detailed in the next instalment of the series. There is no harm in having a static connection to the water gauge, ie a pressure gauge where there is no movement of steam or water through the manifold. I agree that there must not be a connection to the blower or injector etc. from the water gauge. This would have a misleading effect on the water level in the water gauge.

I look forward to seeing a photograph of the completed portable made by JasonB.
4 March 2012 at 17:21 #86486
JasonB
Moderator
@jasonb
Thanks David and also Tony for confirming teh tube sizes, any chance of confirming teh sheet thicknesses for those that may want to know, I would have thought the 3/32" can be replaced with 2.5mm but it would be nice to get Tony to confirm if there is sufficient in his calculations so 3mm can be used where 1/8" is specified and going thicker takes quite a bit of forming.

Unfortunately I'm unlikely to be building tisi engine, I really query these things as I quite regularly get beginners PMing or e-mailing me with questions as they don't seem to want to ask on an open forum and being the helpful chap that I am I like to be able to help. Should Tony want to see some of my work to confirm that I'm not an armchair engineer with nothing to do but pick issues with drawings then he is more than welcome to look here here and here

Jason

PS where does the second regulator bush go? or is there another drawing to follow which shows its location.
4 March 2012 at 17:58 #86488
David Costello
Participant
@davidcostello75947
Jason has got too much experience to even think about building it David.
4 March 2012 at 18:22 #86489
JasonB
Moderator
@jasonb
Its not that David C, just too many projects of my own and the odd commission, and you should know that if I did do a portable it would have to be a Fowler, maybe one of the big ones they supplied to Sena Sugar Mills

Actually I think this engine could be the ideal step for say someone who may have done a couple of bar stock or stuart type engines and wants to move up to road steam as it introduces them to sheet metal work, silver soldering, riviting, fabrication etc. Just like to see that all the info is there and its best to query it at the time than when someone comes to make the engine a few years down the line.

J
4 March 2012 at 18:27 #86490
Sub Mandrel
Participant
@submandrel
Call me stupid, but I couldn't see the overall length of the boiler (or dimensions that added up to it) on the plan. I may be mistaken.

Neil
4 March 2012 at 18:37 #86494
JasonB
Moderator
@jasonb
Your not, also missing the length of all the flanges on the firebox and maybe the odd thickening pad to mount the crank bearings on would not go amiss.

Also no dim for how far the inner firebox projects below the foundation ring, rear elevation should also show inner box protruding below if you want to get picky

Edited By JasonB on 04/03/2012 18:49:22
4 March 2012 at 21:34 #86524
Sub Mandrel
Participant
@submandrel
As you say it's a realistic prospect for someone who hasn't got the time or inclination to make a full blown loco or traction engine, and the finished model looks really good.

It's a shame the errors could confuse a beginner, if a supplier took on the drawings and corrected them and added a few notes and sold them with a special materials pack, it might be quite popular.

Neil
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