Building Kozo's New Shay locomotive

[crueby]

Fantastic build thread. I've been following from the start. It has inspired me to build. My copy of the book arrived yesterday and I haven't put it down since.

Thanks! Hope you post some pictures as you build yours. The whole thing looked daunting at first, but its just a lot of individual easy parts.

 

[crueby]

On to finishing up the safety valves. The inner stem for these is a steel ball held in a little holder on a shaft. To make, took a brass rod, drilled the end for the ball (drilled just over half as deep as the ball), and drilled through for the steel shaft it attaches to. Then, used the parting tool to notch down the end and the upper shank.

Parted them off, and inserted the balls. One was a nice snap-in fit, the other needed at drop of loctite to hold it in place. Teeny little parts!

Third photo shows the parts so far - the valve bodies and the ball holders.

Next up was to make the adjusting body - it screws into the main body, and guides the ball holder. A spring between them is compressed the more this part is screwed in. Started out by drilling the end for steam passage, and turning down the shank to size.

Then, turned it around in the chuck and threaded the opposite end, and turned down the little protruding nub at the end.

Last step on that part is to mill off the sides at the lower end, exposing the end of the steam passage a little. This was left a little short, will be adjusted by filing the sholder back as needed to get the blowoff and reset pressures right - will do that later on.

Next photo shows all the parts for the valves so far, just need to make the locking nuts.

Last photo shows the valves all assembled and on the throttle body. They will be covered by the steam dome, with holes in the top of the dome above each one to let out the steam.

Next up will be to make the snifting valve, that should be a quick little one, just a simple check valve. After that I can get started on the steam and sand domes.

 

[crueby]

One last bit for today - made the snifting valve, which allows air into the engine when the throttle is closed so it does not hit a sudden vacuum. It is a simple check valve, with a steel ball under a cap. When the throttle is open, steam goes up into the valve body and pushes the ball into the valve seat in the cap. When the throttle is closed, the ball falls/gets sucked down onto the end of the valve body, which has a slot so the ball cant seal against it.

First photo shows making the valve body from a piece of hex bar. Hole drilled all the way through for the steam passage, and turned down/threaded the ends. One end got a small slot cut in it.

Second photo shows the pieces made - you can see the slot at the right end of the valve body. The cap was drilled/threaded, and the bottom of the hole extended a little with a boring bar to leave a raised valve seat (a little past a square bottom hole) that was punched with a steel ball to form the seat.

Last photo shows both safety valves and the little snifting valve in place on the boiler. Ready to start the steam dome...

 

[crueby]

Time to make the donuts!

Well, an aluminum one, anyway... The steam dome base started out as a bar of aluminum (did not have any brass that large, and it will be painted anyway, so I am using what I got). Drilled/countersunk the holes that the handrails will go in (visible at the taop of the first photo - the little hole in the middle/top), and then bored out the center to size, halfway through.

Then, turned it around and bored the other side out, a little smaller. The step that left in the center will be used to hold it for milling later.

With the center done, went back and turned the outside down. There is a step at the top for the steam dome to rest into, then a straight section that flares out to the outer diameter. After the rest is milled, that bottom thicker area gets filed down to flare into the shape of the boiler, just like the smokestack base did.

In the fourth photo, the base is sitting on the boiler where it will go around the throttle body. As you can see, it does not sit down on the curve of the boiler yet.

Here is where the step I left in the center bore gets used - turned a brass disc to fit the bore, and used that to bolt the piece to a square block held in the vise. In Kozos' book, he uses an angle iron to bolt it to the lathe faceplate for this step. My little Sherline does not have the throw to do this, so I am using the mill instead. I made a paper template of the top of the boiler, and transfered that to a wood block, which you can see to the right of the mill cutter. That curved top will serve as a guide for setting the depth/width of each pass on the mill. As long as I get close to the template without cutting into it, I will duplicate that curve in the base.

Next photo shows it after a set of passes with the mill - you can see how the curve is replicated in the base piece. I then took the little steps off with a sanding drum and filed it to a good fit on the boiler.

Last milling step was to cut a slot for the throttle valve stem to stick through.

Last photo shows the base test fit to the boiler/throttle. Still need to file the curve into the sides of the base - will show that next time...

 

[RonGinger]

That plywood template is a very clever idea. I am really enjoying your work and look forward every day to hear what you have done, and see the great photos.

Are you going to bring this to Cabin Fever or NAMES? I would really like to see it.

 

[crueby]

That plywood template is a very clever idea. I am really enjoying your work and look forward every day to hear what you have done, and see the great photos.

Are you going to bring this to Cabin Fever or NAMES? I would really like to see it.

Might take it to cabin fever.... Depends what other trips are going on then. Never been to Names. How big a show is that one? Went to cabin fever last year, that was a fun one.

 

[RonGinger]

NAMES is about the same number of exhibitors, but a much smaller floor space so limited in vendors and things like the G scale trains and model boat pond. I have been to all but the first NAMES, and all of the Cabin Fever shows, and hope to continue to make it to both. I will admit, if I had to give up one show I would give up NAMES before Cabin Fever.

 

[SilverSanJuan]

More excellent progress! Thanks for continuing with the detailed photos and descriptions. They are very appreciated.

My thoughts on the steam vs. air for setting your relief valves. The key differences being the temperature and the mass of the steam vs. the temperature and mass of air. The temperature will affect how much relaxation there is in the spring, thus how much steam pressure is required to overcome the spring. Also, steam molecules are more massive than air molecules and have more kinetic energy to boot. So the interaction between the steam and the valve is much different from that of air.

An observation on your barbed nipple for the the blowown valve... You could also attach a rubber hose with a nozzle to steam clean your loco after a running day. Many live steamers use this method to clean their locomotives.

Todd

 

[crueby]

Todd - thanks for the tips/info!

Just about done with the steam dome - just need to make the hold-down screw and the handrail stanchions. First up was to finish the base - last time had it fitted to the boiler, first photo here shows it after filing down the base to blend it with the boiler. Started with some coarse files (more of a rasp, really) and worked down to fine file an sandpaper to smooth it up. The hole in the side will be threaded for the handrail stanchion.

For the dome itself, started with another piece of the aluminum (that is hard to type!), turned a step in the base to match the base, and drilled a starter hole for boring out the center. The chamber in the center is to make room for the safety/snifter valves. It does not go all the way through, so the starter hole was made to same depth as finished chamber.

A bunch of shavings later, had the chamber half done. To make it easier to clear chips/shavings, I bored out the hole half-depth first, then went back and took it down to full depth (almost 1.5" deep).

After the inside was done, turned the piece around in the chuck, holding it with brass shims on the chuck jaws so it would not get marked up, and took the outside down to size at the top. Also, made up a card stock template for the curve at the top - this is important to follow, since going too deep could break through into the inner chamber.

A bunch of nibbling away at the outside, checking frequently with the template, and filing it smooth when the shape was reached, the outside shape is done.

Then, drilled the holes in the top - center for hold-down screw, outer ones for safety valves.

Last photo shows the completed dome sitting on the base. Just need to make the screw and the handrail stanchions, and it will be ready for paint.

Now, need to duplicate most of that same process for the sand dome. That one differs in two ways - much smaller chamber (just need room for water fill plug), and since that dome will sit on the tapered part of the boiler, the curve cut in the base will need to be done at a matching angle. Will probably use same setup, but with the vise on the tilt table - the same process should still work.

 

[swst]

Hi crueby,
I like your posts very much and follow up each thread.
Please advise where you buy the raw material "Copper, Brass & Aluminum" to build the model locomotive and the price of these material per pound.

Rgds
Sunny

 

[crueby]

Hi crueby,
I like your posts very much and follow up each thread.
Please advise where you buy the raw material "Copper, Brass & Aluminum" to build the model locomotive and the price of these material per pound.

Rgds
Sunny

Hi Sunny,

I have been getting most of the material at onlinemetals.com and at yarde.com. At yarde metals, they have a "drop zone" area on thier site with offcuts from thier commercial sales, limited selection but great prices, mostly larger sizes. At onlinemetals, I signed up for thier email list, and get a lot of 20 to 30 percent off coupons. They have a big selection. I dont know the pound price, but you can get that from their sites.
Chris

 

[crueby]

Next up is the sand dome base, which sits over the water fill plug on the tapered part of the boiler. It was made pretty much the same way as the steam dome base, but since it has to sit on a slanted surface the piece needed to be tilted when milling the bottom.

Started out with another chunk of aluminum, bored out the center just like on the steam dome, and drilled/countersunk the holes in the sides for the handrail stanchions.

Then, tilted up the vise to 45 degrees and drilled the holes for the sand dispensing tubes. there are a pair of these on either side. To start the holes, used the mill to make a flat.


Back on the lathe, turned down the lip on the top and turned in a starting curve for the side bevel - this removes the bulk of the material possible on the lathe, saves filing time later on when blending the curve down to the boiler.

Then, back to the mill, with the base mounted with an inner disc just like I did on the steam dome (see previous post for that if you came in late). Again, like with the steam dome, made a card stock template of the curve of the boiler where the base will go, and fixed it in place at correct height next to the base. The base is held at an angle this time that matches the angle of the boiler top surface.

Next photo shows the piece from the side, to show the template in use. For each pass with the mill, I lowered the headstock a little, and cranked the table to the forward/back till the mill just touched the template, then ran the table across side to side to cut a step at that setting. On this base I used smaller steps, which should speed up the filing.

With the milling done, time to test fit the base on the boiler. Not bad, should not take long to get a close fit with some filing to smooth out the steps and match the curve - since the boiler is tapered, one curve wont fit exact at front and back of the base, so I got it close and will fine tune it with the files.

Last photo shows the two domes so far - really changes the look of it yet again. Next time I'll get the sand dome base fitted, and blend in the side curves like the steam dome is. Then, on to making the dome itself, which will be some straightforward lathe work...

 

[fuzzymuff]

Hi Crueby.
What a fantastic build so far. You really show how versatile the Sherline lathe and miling machine are.
Graham.

 

[crueby]

Hi Crueby.
What a fantastic build so far. You really show how versatile the Sherline lathe and miling machine are.
Graham.

Thanks Graham - sometimes it would be handy to have a larger machine, but a little ingenuity and they can do the job.

 

[crueby]

Coming down the home stretch to getting started on the actual engine (8 months in to this point). Made the handrail stanchions today - they are standoffs that hold the handrail around the top of the boiler. Started with some brass rod, drilled the cross hole for the rail, and threaded the end.

Then, moved the end out a little, and used the parting tool to cut into the shank for the post portion. The material is thin, so took in stages to get the whole shank done without bending it (next 3 photos).





Around the cross hole, used a combination of the parting tool and a small file to round the end before parting it off.

Sixth photo shows the handrails in place.

Last photo shows the handrails, plus the sand tubes from the sand dome in place.

Next up is to make the steam bracket/base, which form the mounting point for the engine on the side of the boiler. Kozo designed it so that the steam manifold to the engine is mounted on the side of the boiler where it stays hot, keeping the steam from condensing before getting to the engine. That will be the last piece before starting the engine parts (wahoo!).

 

[SilverSanJuan]

Beautiful! She's really looking like a locomotive now.

 

[crueby]

The steam bracket and base are well along now - the base is a simple slab shape with one side milled out to conform to the curve on the side of the boiler. In the book, Kozo turns this curve on the lathe, holding the base on a long L-bracket on the faceplate. My lathe does not have the capacity for that, so I made a template from the boiler for the curve, and traced the curve onto the ends of the brass piece, and milled down to that. One thing I have had trouble with in the past on milling or cutting off one side of a large bar is the bar deforming as the side is cut away, due to the stresses in the metal from when it was rolled to shape in the factory. I have gotten in the habit on pieces like this of doing a stress-relieving operation on it, which is simply putting it in the oven at 500F for an hour, and letting it cool naturally. This gets rid of the internal stresses without changing the hardness - never had a problem since. After milling to shape, I transferred the locations of the mounting bolts already in the boiler to the piece and drilled matching holes in the base. Machining: process of removing all the excess swarf from bar stock to reveal the finished part.

For the steam bracket itself, this is another slab shape, but left rectangular. It has holes down the length for both steam inlet and exhaust, with passages running from those holes to each of the three cylinders. Started out drilling the exhaust passage.

Then, counter drilled the end to a larger diameter,

and bored an even larger diameter at the very end. These larger sections are to take the exhaust pipe.

After that, it was a matter of drilling sets of holes into the passages at each cylinder. Lots of these, I will not show the entire sequence, better left to the plans in the book. Suffice to say, LOTS of holes, both in the face and diagonally up from the bottom to connect all the passages and to form mounts for the cylinders.



Last two photos show the state of the base and bracket at this point - still need to go back and silver solder in plugs in the extra holes, where passages were formed but need to be dead-ended. Also, will make up the steam inlet fitting for the top - will show that next time (out of time for the day, time to head off to archery league). One more day should wrap up these pieces, then its time to make the cylinders!

 

[crueby]

All right - got the steam bracket finished (added the steam inlet, got the plugs silver soldered in). It will form the platform that the engine will build upon.

The cylinder stock starts out as some 1-5/8" brass rod (stress relieved along with the steam bracket base the other day), that is milled down to square (Kozo does this a lot for square or rectangular stock). I have a big chunk of that size that I picked up as a drop from Yarde Metals. So, first step was to set it up with the fly cutter and take down the sides till square (since I stress relieved it, no need to flip back and forth, could take down each side in full). Several passes per side later, and lots of chips to vacuum up, bar was down to size...





Then, rough cut the bar to length to give the three cylinder blocks - left them a little long to trim up in the lathe.

I mounted each one in the 4-jaw, centered up with a dial indicator, and squared up one end, then reversed it to square up the other.

With the blocks squared up, but still a little long, I measured the length of each one and marked the length on the side. Quick calculation to determine how much to remove off the end to get them all down to final dimension.

Then, put them back in the 4-jaw, and took them down that amount. Last photo shows the three blocks next to where they will mount on the steam bracket manifold. Note that they are not evenly spaced - the leftmost one will have the steam chest on the left, the other two will have the steam chests on the right. This means the first cylinder will have several of its ports/etc on the opposite side from the other two. In order to keep track of which is which I number stamped each one in the upper corner.

Next time - boring the cylinder...

 

[SilverSanJuan]

I wonder why Kozo starts with round stock? Was it just what he had on hand? Why not just start with square bar?

 

[crueby]

I wonder why Kozo starts with round stock? Was it just what he had on hand? Why not just start with square bar?

I think since you can make lots of sizes of square from a few sizes of round. Saves buying a dozen sizes of large square bar. I do same for hex, turn part from round, then mill hex at end for bolt head.