Unsure about drawing for Tubal Cains ‘Polly’ boiler

[Chris machinParticipant @chrismachin]

Hi All ,

hare’s a pic of the drawing of the little boiler for Tubal Cains ‘Polly’ :

 

[IMG]http://i5.photobucket.com/albums/y185/whitebeetle/002.jpg[/IMG]

 

I’m unsure about the drawing regarding the end caps.I have marked on the drawing what i assume are where the end caps are fitted but there is another line on the drawing top and bottom that i’ve marked with a ‘?’

Probably a silly question but is this another plate accross the bottom because i can’t see any explanation of this in the text.

 

Any help appreciated

Chris

[Chris machinParticipant @chrismachin]

[Chris machinParticipant @chrismachin]

http://i5.photobucket.com/albums/y185/whitebeetle/002.jpg

 

[JasonBModerator @jasonb]

The end plates have to be “Flanged” that means that a flat disc is bent over a round former in effect giving a dish with straight sides, these sides give a greater surface area for the folder to form a strong joint.

 

The lines you see are the rim of dish

 

J

[JasonBModerator @jasonb]

Take a look at this post by Stew “potty” Hart, the sketch shows how the tubeplate at the front of the boiler is formed and you can see it on the right of the first photo

 

J

[Chris machinParticipant @chrismachin]

Hi , Yep i understand that but why are there two horizontal lines top and bottom ? isn’t the end cap just one line with the flanged sides against the vertical sides of the boiler ?

[Chris machinParticipant @chrismachin]

 

Thanks for that , yep got it now !!

 

Only been on this forum a few days and the help from everyone has been much appreciated. Thanks again , there will be plenty more beginneres questions !

 

Chris.

[Bill StarlingParticipant @billstarling10428]

Dear Chris,

I’m interested in your Polly project, having made two in consecutive years on the SMEE training courses. I enjoyed the first so much I went back for another go – despite it being a bit of a drag from Norfolk. If you are in reach of London it’s really worth considering going on one. The next one starts on 19th May – see http://www.sm-ee.co.uk/. You’ll get lead gently through the construction, with expert help at all stages, and learn a lot all round the subject of model engineering.

(Hope this is not considered to be a commercial post!)

Bill.

[TerrydParticipant @terryd72465]

Posted by Chris Machin 1 on 25/01/2012 17:45:39:

Hi All ,

hare’s a pic of the drawing of the little boiler for Tubal Cains ‘Polly’ :…………………….

 

……………….I’m unsure about the drawing regarding the end caps…………………………

 

Any help appreciated

Chris

Hi Chris,

 

Reading engineering drawings can be a bit of a black art for the beginner with no experience of them. They incorporate various standard methods which seasoned engineers will take for granted.

 

In answer to this part of your question, the confusion may arise due to the way standard engineering drawings are made. The lines you indicate are the bottom of the end caps. The lower end cap is ‘inverted’ and inserted into the bottom of the boiler. I have made a sketch which shows three drawings of the sort of views of the same boiler construction similar to a ‘Polly’ which I hope explains what I mean.

 

I have indicated with arrows the lines you questioned.

 

Hope that helps,

Best regards

Terry

[JasonBModerator @jasonb]

Thanks Terry I was searching around for a picture on teh net, even the one of Stew’s is wrong as the section does not include the “mistery lines”

 

J

[Roger WoollettParticipant @rogerwoollett53105]

Posted by Bill Starling on 25/01/2012 21:55:54:

Dear Chris,

I’m interested in your Polly project, having made two in consecutive years on the SMEE training courses. I enjoyed the first so much I went back for another go – despite it being a bit of a drag from Norfolk. If you are in reach of London it’s really worth considering going on one. The next one starts on 19th May – see http://www.sm-ee.co.uk/. You’ll get lead gently through the construction, with expert help at all stages, and learn a lot all round the subject of model engineering.

(Hope this is not considered to be a commercial post!)

Bill.

Thanks for the plug Bill. We are now taking bookings for the 2012 courses.

 

Roger Woollett

[Ian S CParticipant @iansc]

Bill, had a look at the SMEE site, interesting. I was looking at the photos of 2010 polly Course, and got about half way down the photos, to Peter Heycock giving voting instructions. There is a locomotive on a shelf that I thought I recognized, There is a picture, and article in Vol 1 No2 of model engineer 1898, there is also adverts for a kit of castings,(some castings are of mild steel).

Nice models, did a similar one but horizontal at the local High School a few years back, but not so ornimental ie not a mantel piece job. Ian S C

[Bill StarlingParticipant @billstarling10428]

Ian,

Perhaps one of the longer standing SMEE members could give us more details of the loco you mention, which I take to be a Stirling single.

SMEE has a wonderful collection of models going back to the mid nineteenth century. These are regularly displayed at ME exhibitions. A particularly nice one is the 2-2-2 loco ‘Jenny Lind’. This – the model – was built around 1870 by John Lellan and recently donated to the Society by his great grandson. Following careful conservation by students at the West Dean College, Chichester, ‘Jenny Lind’ was on show at both the Sandown Park and Alexandra Palace exhibitions. Could someone put a photo up here?

Bill.

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