Building Kozo's New Shay locomotive

[crueby]

FINALLY! got some big progress on the boiler - was finally able to cure those last pesky pinhole leaks and get it to hold pressure. woohoo1 There must be a good way to solve those pinhole leaks (that shoot a super-thin stream under pressure) - I have not found it yet other than repeated reflow. I am pretty sure that a lot of the problem was poor fit on the inside joint rings used to link the tube sections, and also on the strips that closed the tube rings. I was settling for a good structural strength joint, did not make enough effort to get a good tight fit all the way around like I should have. Oh well, still lots learned from first shot at a boiler! This one will spend most of its time as a display model, run on air, so that is acceptable - not worth going back and remaking the whole boiler. Lesson learned for next model though!
So, time to get it polished up and get the boiler jackets on and painted - looks like a session with the paint sprayer is coming up for the jackets, cab, smokebox parts. Will post some pictures when that is done....

 

[SilverSanJuan]

CONGRATULATIONS! That's quite a milestone.

 

[crueby]

Here is the most of the rest of the water gauge assembly - since last time got the last of the parts threaded and silver soldered together. First the mounting ring onto the main column, as well as the crossbars onto the glass holders.

Then, with a piece of rod as an alignment guide in place of the glass, soldered the rest of the parts on. After that, made up the union nuts that go around the glass tube, and compress the o-rings at the ends of the tube.

Made up the top/bottom plugs, and test fitted everything. Getting the tube, o-rings, and nuts all in is a bit fiddly, but it all works. All that is left is to make the valve stem for the drain valve at the bottom of the glass (water drains out of the little tube stub at the very bottom), and bend up/attach the tube that goes to the manifold. Cant do the tube till the boiler is back from the paint shop (corner of the basement) so I can work out the length and curve.

I also took some pictures before starting paint, of the boiler and cab in place. With the boiler jackets on it all looks great in raw brass, but I am going for the painted-real-train look (plus keeping all that brass shiny would be a pain!). Pictures of it painted should be up tomorrow sometime....

 

[SilverSanJuan]

Looks fantastic!

 

[crueby]

Yesterday I posted a couple pictures of the engine before painting the boiler and cab - here are some shots after painting - going to let it set up for a few days before going back and picking out the edge of the floorboard/engine-cover plates in white, as well as the engine numbers on the cab and front plate. Still, looking like a train now - someone come get me in a couple hours, that will be enough time to sit and stare at it! Come a long way from the start of this back in June, very happy with how it has come along.
Again - thanks to all those reading along and encouraging/advising me!

Merry Christmas!!
Chris

 

[crueby]

Could not resist a couple pictures of it under the tree....

 

[Swifty]

Looks really amazing.

Paul.

 

[crueby]

Hope everyone got something better than old rusty swarf in thier stockings this year!

Back from holidays, got a little done in the shop - finished up the water gauge and got the blower valve done too - starting on the blowoff valve now.

First up was to make up the valve stems for the three valves. First, turned down some steel rod to the dimensions for the threaded area as well as the pointed valve portion at the end.

Then threaded the middle area

and took the outer end down to size with the parting tool.

The blowoff valve stem outer end is a little different, it is drilled for a crossbar where the other two get handwheels.

To make the handwheels, I turned the shape of the rim into a brass rod and center drilled it to fit on the end of the valve stem (getting two rims out of this piece, so there is a second rim started behind the first). Then on the rotary table, drilled a series of holes just inside the rim.

Switched to a small end mill, and took little nibbles out of the rim to make it easy to grip.

Back on the lathe, parted off the first, and turned the center in for the second one before parting it off.

Finally, silver soldered the parts together to make the finished valve stems.

The site has a limit on how many photos I can upload at once, so splitting here to another post...

 

[crueby]

Back on the fittings, needed to make up a couple bolts for mounting the water gauge and blower pipe. These bolts are drilled up through the threaded area and cross drilled under the head to form a steam passage. Started with a piece of brass rod long enough for the two bolts, and turned down/threaded/drilled each end.

Then switched the chuck over to the rotary table, and milled the flats into the middle section to form the hex heads on the bolts.

Drilled the cross holes, and parted the two bolts apart.

Next photo shows the first of these bolts holding the water gauge assembly onto the back face of the boiler. You can also see the copper tube from the top of the gauge going back to the manifold on top of the boiler.

Next up was the blower valve (which takes steam and runs it up the smokestack to increase the draft on the fire). One end was turned down and the hex shape milled in as before.

That gave a good surface to chuck in the lathe for turning down and threading the other end.

After cross drilling for the steam passage, next photo shows the valve ready to go. And... Swarf-Pucky!! Just noticed I had the wrong valve stem in the valve for the photo. Oh well, another wardrobe malfunction!

Last photo shows all the valves so far in place (with the correct handwheels this time!). Last up will be the blowdown valve, used to drain the boiler. That will be next time...

 

[crueby]

Catching up on the last of the valve/etc bits in the cab area, got the blowdown valve made (very simaler to the other valves in last couple posts). One change I did from the book was that instead of just being a bit of tube for the exhaust hole, I made it a barbed tube fitting that I can use to attach a tube from the compressor or house supply at shows to run the engine on air. That way I can display it on air, using the normal throttle control without having to remove/replace any fittings.

Second photo shows the completed (for now) cab area - made up the firebox door from brass and steel. There are still more controls to come later - the throttle lever and reversing gear lever plus the valve for water supply from the axle pump.

Last few photos show the loco so far, now that I got the floor plate edges and numbers picked out in white paint - really makes the profile pop.





Next up is the throttle valve assembly, safety/snifter valves, and the steam/sand domes. The domes are larger than any brass stock I have, so they will be turned from aluminum (are not pressure holding, just trim pieces, and will be painted, so material does not matter).....

 

[crueby]

Time to throttle up the build... okay, okay, just time to make the throttle assembly.

Got started with turning down a disc of brass rod to size (first one side as shown in photo, then turned it around and took the other side down).

After that, drilled all the holes through for mounting to the bushing on the boiler, and drilled/tapped all the holes for the safety valves (2 of them), the snifter valve (which allows air to pass into the engine when the throttle is closed), and passages for the steam to come up from the boiler. Lots of holes in all directions, I'll leave that up to Kozo's book to show in detail - took lots of referring back to the plans to make sure it was all correct since there are several intersecting passages.

Last to drill was the passage for the throttle valve stem itself. The outer end of this is larger to take the bushing that leads out.

Fourth photo shows it all together, with the bushing silver soldered in place and the mounting screws sitting in thier holes.

Then I turned attention to the valve stem - the end of this is tapered at 12 and 30 degrees.

Once the end was done, turned down the rest of the stem to size (loose fit in throttle body outer hole).

Then, turned it around and threaded the end to take the clevis.

Last photo shows the pieces so far - next up will be to make the mechanism that threads onto the bushing, which holds the throttle valve stem in a spring loaded setup so that releasing the throttle lever in the cab snaps the throttle closed.

 

[crueby]

I got a PM question that I thought I would anonymously share in case it helps others:

Hello,
I have some questions about some of the details of your beautiful project. I'm amazed at what you can do with the Sherline equipment and would like to know more.
I have never been able to machine steel like you are doing.
First what steel alloy and what tool bit are you using? Second threading what dies and is the setup yours or something you purchased. Thanks for inspiring me to get back to my Sherline. I have more questions that I may ask later.
Thank you,

Most of the Shay I am building is brass, but the wheels/frame/axles are steel. The crankshaft/pistons/etc will also be steel. I prefer to use C360 brass as much as possible since it cuts so easy. For steel, I prefer to use either 12L14 alloy or 303 Stainless, which are easier machining versions. They are not quite as hard or rust-free as other alloys, but they cut much easier. I am using a carbide-insert style tool holder on the lathe - saves a lot of time resharpening a fixed cutter. It is important to use some sort of cutting fluid with steel to keep the cutter from overheating and dulling too quick - I use a few drops of 'ReLion' tapping fluid, since it is what I have on hand. Any of the brands would do the job.
For threading, I have a mix of different brand hand taps, both normal tapered plug taps and bottoming taps. Irwin makes some really good ones, have those at my local hardware store. The tailstock die holder is key for getting outside threads straight on shafts. Mine was one I made, used designs I found by searching the forums and looking in catalogs - simply a chunk of brass milled out to fit the shape of the dies, a setscrew from the side, and a loose shaft running back to the tailstock. I put holes around the edge to let me put in spindle bars (tommy bars) to turn it. Without that holder I could never get the threads to align properly, and would drift to the side. For tapping, I just do that by hand. Again, all threading should use tapping fluid to keep the cutter from binding up, and back it out frequently to clear chips.
Hope all that helps!

 

[SilverSanJuan]

More amazing work coming out of your shop. Nice work on all the various valves and fittings.

Hope you are having a Happy New Year!

Todd

 

[crueby]

First of the new year deserves some new parts! More of the throttle linkages done, ready to move on to the throttle lever end of things.

Started out making up a batch of clevises and link arms out of square brass. Marked out and drilled the holes,

and milled the openings for the arms.

One of the parts is a ring that slides on the throttle bushing, with arms that hold the linkage at one end and a spring at the other. This sliding arm is used to adjust the position and tension on the throttle valve stem when closed. So, drilled a hole in the end of a brass rod and turned the outside down to size. Then, used the mill to put a shallow slot in the side, turned it 180 degrees with the rotary table (the adapter that holds the lathe chuck to the table is a VERY handy item), and milled a matching slot in the other side.

In a piece of sheet brass, I drilled the outer holes in the arms, and milled a slot in the center that made a sliding fit into the grooves in the center ring.

With that part slid into the ring, it was silver soldered together. In the background is another of the arms in the linkage.

Next photo shows milling off the excess from the arms, to leave a tapered shape. Hard silver soldering is something I wish I had learned years ago - would have been able to make better parts much easier for a bunch of the earlier projects....

After filing the ends round, the armed wing was complete.

Last photo shows the parts so far. The holes in the arms closest to you get a spring, and the two left clevises will get a threaded rod sized to fit the distance to the throttle lever in the cab (to be made next).

 

[crueby]

Got on a roll this morning/afternoon and got several parts for the throttle lever assembly made. First up was the lever itself, which is made from a turned handle silver soldered to a bar stock lever. The handle was freehand turned on the lathe, and smoothed out with files.

The reversing lever, made later on in the book, shares a lot of the same kind of parts as the throttle so I am making up two sets. Second photo shows the two handles after parting off and threading the end for a short piece of screw cut off a bolt that will be used to hold it to the bar for silver soldering.

Next up I clamped two lengths of bar steel in the vise and drilled/tapped the end to match the bolt sticking out of the handle.

Next photo shows the two handles soldered up.

The throttle lever is a little shorter, and it has a stub sticking out the side to take the clevis from the throttle assembly.


On to the locking lever, which holds the throttle in one of the preset positions that will be notched into the rails the lever rides between. This is a strange tapered/notched shape, so it was made on the end of a longer bar, and will be sawn off after the rest is shaped. Otherwise there would be no way to hold this little sucker. For scale, that is a 3/8" mill bit in the photos. Started out by taking down the two sides, to make a narrow tounge.

Second step was to drill the pivot hole in the side of the tounge.

Next up was to mount the bar at an angle in the vise, and mill a taper into the tounge side. All these milling operations were done with a series of light cuts, so I did not put too much stress on the part - did not want to risk catching it and bending it.

Then, turned the part over, set it to the angle needed, and milled in the taper on the base of the latch.

Last milling operation was to flip it over again and mill the final taper on the back side of the base. All these operations left a shape that looks a bit like a tiny snow shovel. The 'blade' end of the shovel will latch into notches in the rail, and the hole in the upper end will provide a lifting point for the moving handle.

Next photo shows the parts after milling, but before sawing off the main bar. You can see that there is one part on either end. One will be used for the throttle, one for the reverse lever.

After sawing off and cleaning up the ends, the two parts are done. You can see why it is neccessary to make them from the outer end in - otherwise way too hard to hold safely.

Last photo shows the parts next to the throttle lever itself, after drilling/tapping the rest of the holes in it. Well, most of them - there is one more guide block on the lever that I will make next time.

 

[crueby]

Going on with the throttle lever mechanism - now that the locking lever was made, needed to make the bracket that holds it in place. As with the lever, used a piece of steel longer than needed so there was a way to hold it, and slotted the end to go around the lever and the arm.

Then, needed a slot going crosswise for the 'shovel blade' part of the lever to sit in. I dont have a mill that narrow so I cut it with a jewelers saw (cut down each side, then across the bottom to remove the waste).

After that, I drilled the mounting holes (2-56 thread) in the bracket, and drilled matching holes in the lever arm. First drilled one, ran in a screw, and drilled the second to make sure they would line up.

Last two photos show the assemblies so far (the one at the top in the photo is the reversing lever, bottom is the throttle lever).



Next up will be to make the little bracket/handle that activates the locking lever - that might be a few days, I have some work to finish up on an RC model for a run next weekend. This small work should be good practice for a model I want to make someday - one of George Britnell's Tiny engines.

 

[crueby]

Next up on the throttle/reverse levers is the moving part of the handle that actuates the locking lever. This is another small fiddly part, so am again making up the two pieces together as long as possible to have something solid and rectangular to hold in the vise.

Started out with a rectangular length of steel bar - drilled the end holes, and milled it down to the right width.

Then, turned the bar up on end and milled the slot in the end. This slot will allow the handle to fit over the main bar and the locking arm.

Turned the piece back on its side, and milled out the middle section.

That left the middle section parallel, and one side needs to taper in.

So, angled it in the vise and milled one side to the taper then the other.

At this point, I have done about all I can with the pieces still connected. They were sawn apart, held with a small clamp and the tapered area was rounded over on one side on the grinder.

After that, cut a little strip of sheet spring to size and drilled a hole in the end to hold it to the lever (to drill this spring stock, which is left over clock pendulum spring material, I clamp it between two pieces of wood and drill through the wood into the spring steel - only way to hold it I have come up with).

With all the parts assembled, the two lever arms are done. Last photo shows how pulling the two handles together raises the locking arm up in its slot.

Next up will be to make the sector rails that the levers ride in - those will have notches that the locking arms engage in....

 

[crueby]

Time to make the sector rails for the throttle and reverse levers. They started out as a wide piece of flat bar stock, rough sawn to shape, and the second smaller rail piece was screwed in place using the same holes that will be used to hold the second rail and spacers later.

I got out the faceplate with a piece of wood screwed to it (same piece was used earlier to hold the firebox end plate), and drilled/tapped it for some 10-32 bolts to hold a crossbar to hold the rail in place for milling. With the pivot hole for the lever screwed to the middle of the crossbar, and using that screw as a reference, the whole thing was centered up on the faceplate.

Then, milled the outer radius first, turning it with the rotary table. Stopped once the distance from the pivot to the outer edge matched up with the corresponding distance on the lever arm.

Then moved the table in and milled the radius on the inner edge of the second rail (mill was set to just skim the main rail piece).

With that done, came back with the mill lowered and nibbled out the inner radius on the main piece. Once that was done, just a matter of filing the ends of the rails to a even curve around the screws.

Same sequence was done on the throttle rail pieces....

After all the rail curves were done, I used the same setup to mill out the bases to final shape.

Last photo shows the two sectors with base plates soldered on, and the lever arms all assembled. All that remains on them is to cut the notches for the locking levers to drop into...

 

[crueby]

With the throttle lever assembly done (sawed the slots in the sector for throttle position presets and made the connecting rod to the throttle valve, not much to see, just a rod), time for the two safety valves. Kozo calls out 2 valves, one set slightly under the other ones' pressure for redundancy.

I am making up both at once - this sequence shows one, the other is the same. Started out with a chunk of hex rod, and drilled the smaller through hole.

Then up to the larger bore for the steel ball (drilled then deepened it slightly with a D bit to form a back shoulder).

After that, bored the final outer section for threading.

Threaded that last part M7.

That completed the inside shape (Kozo's book shows it much better than I can here, recommend you refer to the book if you are making one). Final step at that end of the valve body was to round down the outside.

Turned the part around in the chuck, and turned the opposite end down to size

and threaded it to match the threads in the throttle body.

Last photo shows the two safety valve bodies, with the steel balls that will later be fitted to an inner stem (next time).

In the book, Kozo says to use steam pressure to test/set the valves, that using compressed air will give wrong results. Anyone know why, which way that it would be off? Seems like the opening pressure would be the same either way, but I can see that the reset pressure might be different, maybe. Anyone out there have more experience with this behavior? For initial setting I will use air to get it set close, err on the low side, till I can get it tested with steam in the spring (too flipping cold to do much outside this time of year - has been about 5 degrees F recently!).

 

[wirralcnc]

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.