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- Mar 1, 2010
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I am making SandyCs 3 vertical boiler http://www.homemodelenginemachinist.com/index.php?action=tpmod;dl=item107 (all the other sheets are on the download page. Firebird suggested I post the progress.
For machine tools I have a 1930/40s Lorch lathe with a good selection of attachments and a pillar drill. I have a vertical slide for the lathe that allows me to do some limited milling. I do have a reasonable selection of hand tools. So here goes .
I started with rough cutting the 3 tube to length and finishing the ends on the lathe supported by a wooden former on a bearing in the tailstock. Not my idea it came from Martin Evans book Model Locomotive Boilers The former was easily turned on a mandrill using a simple rest and standard wood chisel.
Finishing the barrel ends
Nicely square
The former in the tailstock
Next was the end plates. I had only got through the first few pages of Firebirds making a small boiler when I pitched in and produced my own dies out of aluminum. Later I see Firebird has dispensed with them and now uses a former and beats the annealed copper. As youll see thats what I resorted to in the end.
Turning the male die
Making it fit the internal diameter of the boiler barrel.
Using the male to size the female die.
Turning down the male to be 2x less the thickness of the end plates and using a home made forming tool to finish the internal radii. The form tool was hardened and tempered and ground sharp before using it.
The finished dies
On to the three end plates
Copper sheet marked to size dia + bending allowance + flange size.
Rough cut to size using jigsaw.
I then tried turning these down to the correct size a number of ways, including the double sided tape method used by Firebird and then realized it didnt matter. I just used the rough cut disks and annealed them. They'll get finished later.
In the end I also didnt use the male/ female dies in the manner I had expected. I just used the male die and beat the annealed copper in the time-honored fashion. However I did use the female die as a sizing tool to get the final diameter right. That probably wasnt necessary though.
Putting the finished plates in the three jaw chuck then finished the flanges to size. So no need to cut the disk with any degree of accuracy nor work out how much bending allowance was required. Just make it enough.
One end plate in place in the barrel
The three finished end plates
I now miss a whole lot out on making up and drilling the barrel, end plates and flue. I painted all the parts in engineers blue to assist the marking out and used the surface plate, scribing block to mark it all out.
Once marked out and all the openings centre punched I used a combination of the lathe, V blocks and pillar drill to drill the holes to size.
Centre drilling the holes in the flue for the cross pipes
One point to be made here; I saw positioning the plates in the barrel as a potential problem when silver soldering so elected to use rivets to hold them in position. As the design has components at 45degress around the barrel I added 8 rivet holes around the circumference of each plate, so the end result will look nicer. These rivets wont be riveted but will end up just being silver soldered in.
The turning of the 7 bushes was a relatively simple job although I did realize that the inventories of the steam fitting suppliers are varied so you have to order these components before you start to make the bushes. e.g you make the bush for the water gauge 1/4 x 40TPI and then find you preferred supplier only does ¼ x 32TPI. The same goes for the pressure gauge, safety valve etc. unless you plan to make all those yourself as well.
All the components after pickling
All the sub assemblies loose fitted
The whole thing loose fitted
The end looking from the base
The top
After I've made Firebirds water gauge alignment jig tomorrow is silver soldering the whole thing together. I'll let you know how it goes..........
For machine tools I have a 1930/40s Lorch lathe with a good selection of attachments and a pillar drill. I have a vertical slide for the lathe that allows me to do some limited milling. I do have a reasonable selection of hand tools. So here goes .
I started with rough cutting the 3 tube to length and finishing the ends on the lathe supported by a wooden former on a bearing in the tailstock. Not my idea it came from Martin Evans book Model Locomotive Boilers The former was easily turned on a mandrill using a simple rest and standard wood chisel.
Finishing the barrel ends
Nicely square
The former in the tailstock
Next was the end plates. I had only got through the first few pages of Firebirds making a small boiler when I pitched in and produced my own dies out of aluminum. Later I see Firebird has dispensed with them and now uses a former and beats the annealed copper. As youll see thats what I resorted to in the end.
Turning the male die
Making it fit the internal diameter of the boiler barrel.
Using the male to size the female die.
Turning down the male to be 2x less the thickness of the end plates and using a home made forming tool to finish the internal radii. The form tool was hardened and tempered and ground sharp before using it.
The finished dies
On to the three end plates
Copper sheet marked to size dia + bending allowance + flange size.
Rough cut to size using jigsaw.
I then tried turning these down to the correct size a number of ways, including the double sided tape method used by Firebird and then realized it didnt matter. I just used the rough cut disks and annealed them. They'll get finished later.
In the end I also didnt use the male/ female dies in the manner I had expected. I just used the male die and beat the annealed copper in the time-honored fashion. However I did use the female die as a sizing tool to get the final diameter right. That probably wasnt necessary though.
Putting the finished plates in the three jaw chuck then finished the flanges to size. So no need to cut the disk with any degree of accuracy nor work out how much bending allowance was required. Just make it enough.
One end plate in place in the barrel
The three finished end plates
I now miss a whole lot out on making up and drilling the barrel, end plates and flue. I painted all the parts in engineers blue to assist the marking out and used the surface plate, scribing block to mark it all out.
Once marked out and all the openings centre punched I used a combination of the lathe, V blocks and pillar drill to drill the holes to size.
Centre drilling the holes in the flue for the cross pipes
One point to be made here; I saw positioning the plates in the barrel as a potential problem when silver soldering so elected to use rivets to hold them in position. As the design has components at 45degress around the barrel I added 8 rivet holes around the circumference of each plate, so the end result will look nicer. These rivets wont be riveted but will end up just being silver soldered in.
The turning of the 7 bushes was a relatively simple job although I did realize that the inventories of the steam fitting suppliers are varied so you have to order these components before you start to make the bushes. e.g you make the bush for the water gauge 1/4 x 40TPI and then find you preferred supplier only does ¼ x 32TPI. The same goes for the pressure gauge, safety valve etc. unless you plan to make all those yourself as well.
All the components after pickling
All the sub assemblies loose fitted
The whole thing loose fitted
The end looking from the base
The top
After I've made Firebirds water gauge alignment jig tomorrow is silver soldering the whole thing together. I'll let you know how it goes..........