Coppersmithing a Boiler - Southern Railways Bulleid Pacific
Posted: Thu Mar 03, 2011 5:13 pm
My steam loco mate at MLS, Keith Wood, posted a how-to series on our club's forum and I thought some folks here would find it interesting. So posted here with his permission... is the step-by-step construction of Keith's third copper boiler. He has successfully built a Rob Roy (0-6-0) and a Castle Class (4-6-0), both 3/4" scale, previous to this project.
Feel free to ask questions of Keith here as he does monitor this forum.
Jim Leggett
Montreal Live Steamers
Boiler Building #1
by Keith Wood » Wed Sep 29, 2010 4:17 pm
I have started the construction of my latest project, the boiler for my Southern Railways Bulleid Pacific.
I will endeavour to record each step in construction to provide a guide to anyone else who would like to build a boiler.
I have taken advantage of some new technologies to help with the design and fabrication of the copper plates, everything else will be traditional boiler making as described in Martin Evans book "Model Locomotive Boilers".
The Design.
In order to build a boiler that meets the requirements of the safety fraternity, I selected the LBSC Britannia boiler as my starting point, the prototype locomotive boiler was based upon Oliver Bulleid's design.
The plans provided me with material thicknesses, stay location and spacing, flue sizes etc.
The main difference between the Britannia boiler and the Bulleid boiler being the fact that Bulleid has the tapered portion of the boiler inverted, it is horizontal at the top and tapered underneath, also the full length of the Britannia boiler is tapered where the forward barrel of the Bulleid is parallel.
I used a 3D CAD system to define the geometry, as my day job is a designer, this was relatively quick.
Once the 3D models were created I used the flat pattern development software to create the flat patterns for all the copper plates and the templates for the flanging blocks.
Flanging Block Construction.
I pasted the trimmed flanging block patterns to some thin steel sheet and cut the steel templates to shape.
I work with a gentlemen who does a lot of wood working in his spare time, he was good enough to make the flanging blocks for me (using the steel templates) out of many pieces of maple wood glued together butcher block style, he did a really nice job, he even routered the bend radius on the edges of the blocks. Its such a shame that you only use them once.
Copper Plate Construction.
The flat patterns were printed out on regular copier paper, after verifying that the flat patterns were 1:1 I trimmed the shape and pasted them on to pieces of copper sheet using a glue stick (holds well and is easily removed)
Each copper plate was trimmed using my band saw and hand shear, final shaping was completed by hand filing, each plate was deburred to remove sharp edges.
The boiler plates are:
Backhead, throatplate and outer wrapper are 1/8" copper sheet.
Firebox plates and wrapper, and the tapered barrel are 3/32" copper sheet.
The front barrel is 4 1/8 O/D x 1/8" thick copper tubing that I purchased from a member of my club.
Next episode - Forming the copper.
Feel free to ask questions of Keith here as he does monitor this forum.
Jim Leggett
Montreal Live Steamers
Boiler Building #1
by Keith Wood » Wed Sep 29, 2010 4:17 pm
I have started the construction of my latest project, the boiler for my Southern Railways Bulleid Pacific.
I will endeavour to record each step in construction to provide a guide to anyone else who would like to build a boiler.
I have taken advantage of some new technologies to help with the design and fabrication of the copper plates, everything else will be traditional boiler making as described in Martin Evans book "Model Locomotive Boilers".
The Design.
In order to build a boiler that meets the requirements of the safety fraternity, I selected the LBSC Britannia boiler as my starting point, the prototype locomotive boiler was based upon Oliver Bulleid's design.
The plans provided me with material thicknesses, stay location and spacing, flue sizes etc.
The main difference between the Britannia boiler and the Bulleid boiler being the fact that Bulleid has the tapered portion of the boiler inverted, it is horizontal at the top and tapered underneath, also the full length of the Britannia boiler is tapered where the forward barrel of the Bulleid is parallel.
I used a 3D CAD system to define the geometry, as my day job is a designer, this was relatively quick.
Once the 3D models were created I used the flat pattern development software to create the flat patterns for all the copper plates and the templates for the flanging blocks.
Flanging Block Construction.
I pasted the trimmed flanging block patterns to some thin steel sheet and cut the steel templates to shape.
I work with a gentlemen who does a lot of wood working in his spare time, he was good enough to make the flanging blocks for me (using the steel templates) out of many pieces of maple wood glued together butcher block style, he did a really nice job, he even routered the bend radius on the edges of the blocks. Its such a shame that you only use them once.
Copper Plate Construction.
The flat patterns were printed out on regular copier paper, after verifying that the flat patterns were 1:1 I trimmed the shape and pasted them on to pieces of copper sheet using a glue stick (holds well and is easily removed)
Each copper plate was trimmed using my band saw and hand shear, final shaping was completed by hand filing, each plate was deburred to remove sharp edges.
The boiler plates are:
Backhead, throatplate and outer wrapper are 1/8" copper sheet.
Firebox plates and wrapper, and the tapered barrel are 3/32" copper sheet.
The front barrel is 4 1/8 O/D x 1/8" thick copper tubing that I purchased from a member of my club.
Next episode - Forming the copper.