Building Kozo's New Shay locomotive

[crueby]

Too hot to do anything outside recently, so been spending some time in the shop playing with the Shay model.
I drilled/tapped the right-side hubs for the bevel gears, and got them painted. The holes were drilled using a drilling jig to keep them all the same, same jig will be used to drill the gears. The center hole in the jig was already in the scrap piece of brass, has nothing to do with the jig...

Then got the axles done - pretty straightforward turning of a shoulder on steel rods, with two axles having eccentrics added (held with set screws) that will power pumps for oiling the engine/shafts, as well as the boiler water feed pump. The wheels are held on with high strength loctite.

Included a shot of the wheels set under the frame to see how the overall progress is going - almost looks like a train...

Next up are the bevel gears - I have cut lots of normal flat gears, this will be first time for bevel gears. I have a book on gear cutting plus some articles, looks like a straightforward extension of the normal method, with some extra fiddly steps to keep it interesting. This engine needs 4 pairs of gears, one per axle. Stay tuned for progress pictures, hopefully none of the gears get turned into projectiles for the ol' flintlock!!

[b.lindsey]

It all looks amazing Crueby...most impressive!!

Bill

[crueby]

It all looks amazing Crueby...most impressive!!

Bill

Thanks Bill! Been havng a lot of fun making it - individual skills from a lot of earlier projects coming together with the new ones learned on this one. Kozo has some great tips in his books, been wanting to make a loco for a long time.

Chris

[crueby]

Well, I was going to wait and post the making of the bevel gears for the Shay all in one post, but it turned out I did not have any brass large enough diameter for the ones attached to the wheels so had to order some more (found a chunk of 1-5/8" bar as a drop at a commercial supplier, it should be here later today according to the tracking).
So, I got started with the smaller gears, a 20-tooth gear at 26.57 degrees. These are being done with a 44 tooth-range cutter, module 0.7. First up was to turn the blank on the lathe, with the bevel done with the compound slide

and the rest done with the normal slide. Since the teeth will intersect the post of the gear, the gear is first made with the post on the large side, which later on will be turned off after a new post is hard soldered on the small side of the gear.

With the blank turned in the end of a brass rod, the chuck was moved over to the rotary table, which was set at a 26.57 degree angle to the mill bed. Since that did not leave enough travel on the bed, I got out the heavy plywood extension that I made several years ago for cutting large clock gears.

The teeth were cut in three passes, one normal pass to cut the slot between all the teeth, then two more passes to take a slight wedge off the side of the large end of each tooth to give it the final shape - this is needed since the teeth and the gaps between them need to be tapered on a bevel gear, and the cutter will only do a parallel-sided gap in a single pass. I used the formulas from Ivan Law's book on gear cutting (with the correction from Sine to Cosine that I learned from other's posts - that saved the day!). I tried to get photos showing the process, but they did not come out well enough to show - will try again with the larger gears, hope they show the difference between passes.
As each gear was completed, it was cut off the bar, and the process started again for the next one - 4 gears needed in total.

Once all the gears were cut (they mesh very well with each other, so that is a hopeful sign I did it right, will know for sure once the large gears are made) it was necessary to make a new post for the small end. The posts were turned to the final diameter, with a smaller end that fit snug into the holes in the gears. They were then silver soldered in place.

After soldering, the gears were chucked up in the 4-jaw, and trued using the original post. They were then redrilled through the new post, and the old post turned off. Again, this was needed since the final post coming out of the small end of the gears would have been in the way of the gear cutter.

Once the gears were done, a setscrew was drilled/tapped into the post to hold them on the line shafts. Once the trucks are done, the positions of the gears will be adjusted to mesh well, then the posts will be cross drilled for final pins - the setscrews are just to allow that adjustment before pinning.

[b.lindsey]

Nicely done crueby, and some nice outside the box thinking on the Sherline mill set-up as well!!

Bill

[crueby]

Okay, got the larger bar stock for the 40-tooth bevel gears, and got the first one made tonight (weather was good during the day, so got the canoe out for a paddle first!).

Took the 1 5/8" round stock, and cut down four discs, then center drilled/reamed for the axle, and using the drill guide made for the screw holes in the wheels, drilled out some 3-48 clearance holes. Then bored out the recesses in the center of the gear, which provide clearance for the bearing holders. Then, made up an arbor with the same drill guide, and turned the outside of the blanks to the bevel angle.
With the chuck/arbor moved over to the rotary table on the mill, cut the teeth using same constant-depth method as the small gears. Must have gotten my calculations correct, since they mesh very nicely. Just need to make up the other three....

This was my first build of bevel gears - they seem intimidating to make, but once you have been through it and see the changes each cut makes, it really is a straightforward process. Glad I had made some normal gears first though....!

[wagnmkr]

A fine bit of gear making there for sure. It is good to see the process as I have the Heisler and the Climax books and need to make those gears as well if I proceed.

Excellent photo's and description. Thank You

Cheers,

Tom

[Roger B]

That's some good looking gear work, something I have yet to try 

Still following along   

[crueby]

Got a start on the trucks for the Shay - The lower bolsters are bigger than any rectangular stock I had, so I made the bars from a couple lengths of round rod. In the past, I've run into trouble doing this, having the bars warp on me as I took down the first side. So, before machining, I did a stress-relief session in the oven (500F for an hour) first, let them cool down, and there was absolutely no warping problem. As I understand it the bars get work hardened during the rolling process as they make them, and if you cut one side off the internal stresses built into the bar will cause them to twist to the side. Other alternative is to take a little off one side, turn it 180, take some off the other, and so on. Baking them first to relieve the stresses let me mill off one side down to desired dimensions at a time - easier, and came out dead straight.

Once they were milled to overall length/width/height, I milled the steps in the right ends (which let the drive shafts pass by).

Then, using the tilt table and machine vise, milled the ends and the angled slots in the ends (3 degrees, to give the suspension room to tilt on uneven track). Kozo did this with angled blocks in the vise, but having the tilt table made it an easier setup for me.

After milling, laid out all the attachment holes and spring-end holes, and did a long session of drilling/tapping. Both lower bolsters are the same, except for the mount holes in the center for the brake levers, which are opposite on each bolster.

Finally, made up the bronze bearing blocks and adjustment screws which pre-tension the springs on each axle (there is a sprung vertical movement on the left end of each axle, then the entire truck has springs for movement of the axles as a pair - slick setup they did on them).

Next up will be the rest of the framework for the trucks.... but first, off to the local steam fest later this week! Here is a link to thier site:
http://www.pageantofsteam.org/

[PStechPaul]

Nicely done! There is sure a lot of time and work going into this project. Just looking at all the many parts and machining operations makes me want to take a nap! 

Looking forward to more great photos and seeing this locomotive rise from the raw materials and swarf! 

[crueby]

Nicely done! There is sure a lot of time and work going into this project. Just looking at all the many parts and machining operations makes me want to take a nap! 

Looking forward to more great photos and seeing this locomotive rise from the raw materials and swarf! 

Thanks! Definitely a fun project. Generated a LOT of swarf so far (and spent a lot on materials too! Been haunting suppliers drop piles for deals, saved a lot that way)
This kind of project must be the equivalent of a bunch of standalone motors. Can't praise kozo's books enough, learning a lot.

[crueby]

Got the truck support columns made - they bolt to the lower bolster, and guide the upper bolster on the springs. The angled slots in the upper bolster ride on tongues sticking out of the columns, which allow them to angle side to side and roll forward/back as needed on uneven track. These columns will also hold the upper framework for the rest of the truck structure.
To start, cut some slices off a piece of 1-1/8" square bar stock brass, and milled them down to the final dimensions (16mmx20mmx28mm).
Then, milled in the recess on the inside surface to make the guide tongue/base, a pair at a time. On the outside surface, a recess was milled into the side and the middle was milled to the same depth - this left a pair of columns sticking out. After that, the holes in the top/bottom were drilled/tapped, and the outside face was angled back with a larger mill.

When assembled, the upper bolster is suspended on the main springs, and held from coming out by a small plate screwed to the top of the columns. The upper bolster has a pin in the center that holds it to the crossbar on the main frame, and also has a pair of blocks that ride on the crossbar. The upper bolster is free to move up/down, tilt side to side, and roll forward/back a bit.

Next up is to make the webwork of flat bars for the rest of the truck, and then the really fun bit of milling, the journal blocks that hold the axle bearings. Those are complicated shapes, fortunately Kozo gives a good step by step sequence for milling them out....

[b.lindsey]

Nice progress on the trucks crueby!!  All I can say is that your local brass dealer must love to see you coming in

Bill

[crueby]

Nice progress on the trucks crueby!!  All I can say is that your local brass dealer must love to see you coming in

Bill

Too bad he wont take the bucket of chips back for credit on another bar!

[ths]

It would be a bucket by now, and probably more to come. I have one, due to some swarf melting fantasy, no doubt. Great work, I'm really enjoying watching.
Hugh.