Building Kozo's New Shay locomotive

[ths]

Nice formers you've done there, what gauge copper will the boiler be made from?
Hugh.

[crueby]

Nice formers you've done there, what gauge copper will the boiler be made from?
Hugh.

So far the formers are just roughed out, still need final milling to dimensions. The copper for most of the boiler is 2mm thick, for the firebox shell it is 3mm thick. Kozo designed it with three firetubes and coal fired. I am thinking that I will use a gas fired burner instead for mine.

[crueby]

Next step is done on the boiler former blocks - got them milled down to size. For the round ones, I screwed a sacrificial block to the faceplate, drilled for a bolt on the lathe to ensure the bolt was centered, and screwed that assembly onto my rotary table (which has a screw adapter for centering chucks on the table). Then I could bolt the round formers down and mill them to exact size (spiral mill leaves a finer cut on this wood than the lathe bit does, plus the odd shape ones later would not work on the lathe anyway).

Same was done for the smaller end formers.

For the formers around the firebox, which have a circular end and a straight base, did the same thing but stopped turning the table where it met the straight sections (third photo).

There are also a pair of formers for the forward end of the firebox area, which are just a rectangular section with an arc cut into the top. This needed a different holder, one with a tongue sticking out to bolt the former to (bolt holes needed to be right distance out to put the arc in correct place). I could not use a larger circle for this, since I dont have enough reach on the mill.

On the wider of the two, (fifth photo), there was not enough room to rotate it all the way past the cutter, so I did as much as I could on one side, then finished it up on the other side of the column (did not move the former on its holder to ensure it stayed centered).

With both of the throat formers cut, bolting the together shows the step formed - the arcs are different by the thickness of the copper. This will allow using a pipe section to finish hammering down the flange there - will all become clear when that piece is made. Kozo really thought these formers through, looks like a good sequence he has in the book.

At this point all the formers are cut, milled to shape, and drilled where needed. Still need to go back and round over the corners of the edges the copper will be hammered over - will use a small 1/4 round bit in the trim router for that.

Once that step is done, will be time to start cutting copper sheet! Think I'm gonna cut each blank, and take some of the offcut scraps to experiment with the hammer (have wood and plastic head mallets for the forming)....

[b.lindsey]

Those look great crueby, and it does my heart good to see you using the Sherline to its capacity

Bill

[Tennessee Whiskey]

Crueby, been following quietly. I had a great uncle who was a great auto body man. He used to say you got to treat metal like a young mule; "you try gently at first and then you may have to beat Hell out of it.". You've done a splendid job so far and I only expect the same going forward.

E

[crueby]

Crueby, been following quietly. I had a great uncle who was a great auto body man. He used to say you got to treat metal like a young mule; "you try gently at first and then you may have to beat Hell out of it.". You've done a splendid job so far and I only expect the same going forward.

E

Great saying! Thanks for the encouragement!

[fumopuc]

Hi Crueby, I am also following along quietly. I like the way you are using the Sherlines.

[ths]

I like the way you went about that. Cheers, Hugh.

[crueby]

Thanks guys!

Interesting how many comments I have gotten about doing this project on the Sherline machines - they must have a reputation (obviously undeserved) about being too small to do anything useful with. Definitely too small to make a really large scale engine on, but for small to medium builds they are fine. I have done a bunch of engines, plus 4 clocks, parts for my target guns, parts for the boats, lots of ship model parts....!

Current update (only had a little time to be in the shop today):

Got the corners of the formers rounded over (1/16" radius bit in trim router), and also made the patterns for the endplates out of some card stock (wierd, a step that involves no swarf!).

Next step, trace them out on the 2mm copper sheet and start cutting...

[crueby]

Wow - that worked out a lot easier than I had been expecting. Got the boiler endplates cut out (picture 1) and formed. Annealed the copper with a torch and let it all cool down, then started in on the shaping. Using a plastic-headed hammer started hammering on the exposed flanges - got about 1/3 to 1/2 of the way over very quickly, then as the copper work-hardened it would get to a point were it would just bounce the hammer off. (picture 2) Took all the parts to that stage before continuing. (picture 3)

I took that as a sign that it was work-hardening, and took it back out to reheat and cool down again (about 20 minutes or so to cool, its cold out today). After that, got most of the way over (all the way on the parts that were just straight sections). (picture 4)

Another re-anneal step, and the parts were formed all the way over. (pictures 5 and 6)

The one that needed a fourth anneal was the throat plate, which has two side flanges going one way and the curved section going the other. (picture 7)

Once all the plates were formed, they were given a short soak in the Sparex acid pickle and wire-brushed under running water to clean them back up. Looking very good so far, ready to machine the edges to final dimension (which also gives a fairer surface for silver soldering).

There are still the tube sections and firebox to form, probably will do that after machining the endplates. They will be simpler bends, since they wont have flanges to deal with.

[ths]

Well done, they certainly look the goods. Hugh.

[b.lindsey]

You are moving right along Hugh...those look good!!

Bill

[jschoenly]

I used to sell Sherline and used a few pieces in that time.  They may be small, but that doesn't mean they don't work.  It's all about the user and the ingenuity.  I had to make a fuel pump plunger for a large gas engine one time and the Sherline was the most convenient machine available.  It got buried in the process but it worked like a champ for all the brass removal!

Keep up the great work!  This flanged sheets for the boiler look fantastic!  It's really fun to see your posts coming in!

[crueby]

Jschoenly - that was a LOT of brass chips, but came out looking great. You are right - sometimes it takes some extra thought (think the brits call it 'bodging' or some such!) to figure a way to do a large part, but I think that is part of the fun!

I was surprised at how well the copper would take the extra shaping - sort of like really really (really) thick clay. Learning a lot on this project - opening up all sorts of ideas for future ones.

[crueby]

The boiler front end plate machining started with drilling holes for the firebox studs, the blower tube fitting, and starter holes for boring the firetub holes.

In the book, Kozo mounts the front plate (and later the firebox plates) to the lathe faceplate to cut the holes to size with a boring bit (drills this big would never give a clean round hole). However, this is another case where a little ingenuity was needed to do the operation on a small lathe. I could just get the front plate offset enough on the lathe, with the riser block in, but there is not enough clearance to do the same on the firebox plate. So, am doing those operations on the mill, which has a slightly longer reach, plus using the rotary table means the mill cutter only has to reach the inside edge of the hole, not the center. So, I screwed the plate to a piece of wood on the faceplate (same one used earlier to mill the formers), and milled the three firetube holes out to size.

After all the holes were done, checked the fit of the tubes/fittings (third photo). The blower tube fitting does not get soldered in now, that comes along with the firetube assembly later.

Last part of the front plate to make were the two stiffening ribs on the inside of the plate. I trimmed out a couple of cardboard templates to get the shape figured out (the radius of the flange on the plate is a little tricky to match), then cut and filed up a pair of ribs out of copper.

The two ribs interlock to form a 90 degree angle. The ends were filed off at a rolling angle to match the front plate shape.

With the two ribs clamped in place, they were silver soldered to the plate.

Then, the plate was screwed back down to the rotary table, centered up, and the outside edge milled to the dimension needed.

Last, the two firebox studs were soldered on (these take screws from the inside of the firebox to hold it in place).

Next up, simaler steps on the front firebox plate...