Building Kozo's New Shay locomotive

[SilverSanJuan]

If you haven't checked out Ed's conversion of Kozo's shay to a three truck #1 gauge live steam, then you must.
https://www.flickr.com/photos/edhume3/sets/72157614192042835/

Todd

 

[crueby]

Not a lot to show today, since pictures can't show things moving smoothly (and I can't video while using both hands to hold engine/turn crank). The main bearings and crank bearings have all been lapped in with some TimeSaver compound, and you can still see all my temporary markings on parts so I get them all back on the same shaft and side (learned that one the hard way on a previous model - what a pain to sort out unmarked bearing halves that got mixed up!). So, a picture showing things during reassembly - the pistons are all set on the crossheads, o-rings are there in the piston ron bearings and in the pistons themselves.

I want to make up the gaskets for the top/bottom of the cylinders before putting the cylinders back in place, so that will be next. Then I am going to bolt it up on the loco and get some video of it rolling back/forth on the display track and everything so far spinning. That should be fun (listen for my cackling in the background!). Been busy with other stuff the last couple days so that will probably not be till late friday or saturday. This is where it all starts to come together - fun time!

 

[crueby]

If you haven't checked out Ed's conversion of Kozo's shay to a three truck #1 gauge live steam, then you must.
https://www.flickr.com/photos/edhume3/sets/72157614192042835/

Todd

Todd - thanks for the link!

WOW! Ed - you did an amazing job on your Shay - very impressed! :bow:

I really like the butane burner setup - is that your own design, or an existing one? I'd love to make one like that for mine. Are plans available for that burner/tank design??

 

[edhume3]

Hi Crueby,

Thanks for the praise.

The butane burner is my own design based on ideas from Morewood's Raritan propane burner. It is working well and it is convenient. I have a mix of hand sketches and CAD files for the parts. I'll look into pulling the materials together, but not before this weekend - I am prepping for the Chile Fest steamup in Houston. The filler valve is a Ronson lighter repair part that you can find on ebay which uses a tightening tool and a special metric tap.

 

[crueby]

Hi Crueby,

Thanks for the praise.

The butane burner is my own design based on ideas from Morewood's Raritan propane burner. It is working well and it is convenient. I have a mix of hand sketches and CAD files for the parts. I'll look into pulling the materials together, but not before this weekend - I am prepping for the Chile Fest steamup in Houston. The filler valve is a Ronson lighter repair part that you can find on ebay which uses a tightening tool and a special metric tap.

Thanks for any info. Enjoy the steam fest! Up here in upstate NY it is very cold, very snowy - just spent the day clearing snow off the roofs at my house and my mothers' house (arms are like rubber now!). Looking forward to spring!

Chris

 

[crueby]

Got the engine parts so far all assembled again and fit on the loco, and could not resist pushing it back and forth on the display stand to watch it all spin. No valve train yet, so cannot run it for real, but getting close! Below are a couple photos, plus a link to a short video of it moving (dont think the camera picked up the sound of my face cracking with the smiles!). Would have posted this earlier but right at the end of the video you can hear the phone ring - had to go over and shovel a few feet of snow off my mothers' roof, and came home and did the shallow pitch part of mine too. Crazy winter this year... yes, I can hear you guys Down Under snickering from hear, and complaining about the heat!

[ame]https://www.youtube.com/watch?v=kFhupERdyAI&feature=player_detailpage[/ame]

 

[SilverSanJuan]

Outstanding! Looks like it runs pretty smoothly.

Todd

 

[crueby]

Outstanding! Looks like it runs pretty smoothly.

Todd

Only adjustment I had to make yesterday was on the o-ring holders for the piston rod seals - had to take them out a few thou, the compression on the o-rings was just a little too high. I had forgotten to measure the actual o-rings I had and look them up in the table at the back of the book where he gives the dimensions for a smooth sealing fit - the dimensions on the plans were for the metric rings, I had the nearest inch size to match the piston rod stock I had. fortunately it was a small difference so I did not have to remake the parts.
Other than that it all went together well - very happy!

 

[bouch]

Got the engine parts so far all assembled again and fit on the loco, and could not resist pushing it back and forth on the display stand to watch it all spin. No valve train yet, so cannot run it for real, but getting close! Below are a couple photos, plus a link to a short video of it moving (dont think the camera picked up the sound of my face cracking with the smiles!). Would have posted this earlier but right at the end of the video you can hear the phone ring - had to go over and shovel a few feet of snow off my mothers' roof, and came home and did the shallow pitch part of mine too. Crazy winter this year... yes, I can hear you guys Down Under snickering from hear, and complaining about the heat!

https://www.youtube.com/watch?v=kFhupERdyAI&feature=player_detailpage

View attachment 75579

View attachment 75580

View attachment 75581

Thanx for the video! Love watching the motion on a shay!

 

[crueby]

Alrighty - on to the valve stem assemblies. Both the valve slider and the valve crosshead are bronze, and were first milled to outer dimensions from a larger piece of rod. Both will be made in a group of three to make it easy to position/hold in the vise.

First shaping operation on the sliders was to mill the rectangular recess in the face side. This was done as a plunge cut with a center-cutting end mill, and the shape traced into the bronze.

Next, the piece was turned over and a slot run down the length with the mill. This will form the groove that the square adjusting nuts sit in.

With the piece sticking out the side of the vise, cross-slots were milled in to form the groove that the valve stem rod will sit in.

Then with the piece held at a 45 degree angle in the vise, the tops of the sliders were tapered back. Since the angles were all 45, it was possible to do both sides of each top with this one position, just had to raise the cutter for each side and run it back and forth.

Last shaping was to also taper the side faces.

With all the shaping done, the sliders were cut apart and trimmed to length with the mill. This photo shows the three sliders all complete.

With the sliders done, it was time to move on to the valve crossheads. On the Shay, the valve stems come down to a crosshead/guide assembly that the reversing gear connects to. This keeps the angular motion from the eccentric from being transfered to the valve stem. To start, another rectangular section of bronze was milled to size, then a step cut into each side. This step will allow the guide to hang onto the crosshead.

Next step was to drill the cross-hole in each of the three pieces (all three are gotten out of this one strip). This cross hole will be threaded for the pivot pin from the reversing gear linkage.

The piece was turned on its side, and notches cut into the edge to form the protruding post at the top of the crosshead.

Next photo shows the crossheads so far, with the major shaping and cross holes drilled. The three parts were then cut from this strip.

The cut ends were then trimmed to length with the end mill. The other part visible on the right was to keep the vise jaws from twisting.

Last step was to drill through the ends for the hole to hold the valve stem, plus a lock screw on the bottom that keeps the cross pin from un-threading itself.

Last two photos show the three valve stem assemblies complete - made up the valve stems (stainless rod threaded at each end) plus the square nuts. You can just see that the nuts have a short round section on the end. I did not have an end mill quite small enough to match the diameter of the stem rods, so this projection keeps the square nut centered on the slider.



With the sliders all done, next step is the valve crosshead guide, which bolts to the piston crosshead columns...

 

[SilverSanJuan]

Dang, those are some tiny pieces! Nice work.

Todd

 

[crueby]

Dang, those are some tiny pieces! Nice work.

Todd

Thanks! Such little pieces definitely take a little planning in how to hold them for cutting. It will be good practise for when I build one of Britnells' Tiny engines someday...!

 

[crueby]

The valve crossheads ride on a guide bolted to the piston columns. These guides have brass bases and stainless steel retaining plates. The bases started out as a length of brass bar, milled down to outer dimensions with the fly cutter. Then the stepped sides were cut in with an end mill. The lines on the end are a guide to the final shape - they are just there so I can tell at a glance which side is which, the cuts were measured from the upper edge.

Once both sides were stepped in, the top was grooved down the center - the crosshead will rest on the two upper rails.

A simaler groove was cut in the bottom, to give estra clearance to the piston crosshead.

Next photo shows the guide block complete, ready to be cut into the three individual guides.

After cutting the blocks from the larger piece and trimming them to length with the mill, holes were drilled/tapped into the sides to hold the steel retainers.

Last step was to drill the mount holes to match the ones in the piston columns.

Last photo shows the guide blocks complete - the one on the left as a valve guide resting on top where it will be held by the retainers.

 

[crueby]

Got the rest of the valve guides made. The retainers are milled out of some stainless steel. Such skinny strips were a challenge to figure out how to hold, what I wound up doing was milling them in pairs out of a larger bar. With the outside taken down to dimension, I milled the center out to form a u-shape, then hacksawed down the middle to split them into two pieces.

With each piece held in the vise, the sawn edge was taken down smooth with the mill.

Next photo shows the two strips after this shaping.

Last steps were to drill the mount holes, and saw the strips into the 6 retainers.

Last two photos show the parts so far assembled. The guide blocks look to need just a little tweaking to get them to line up perfect with the valve rods, looks like the the tolerances stacked up on me and they are just a few thou short. Nothing a strip of thin shim stock wont cure.



Next up will be the reversing gear parts - lots and lots of little parts. Good thing to work on while the weather is still so bad!

 

[crueby]

Quick update from this morning - got the guide shims worked out and made (just some thin shim brass with holes to match the guide bases), and the first guide installed along with the valve slider. Picture below shows that first one in place, two more to go. I may skip adding the valve slider on the middle one till the reverse gear is done, since I'll have to dismantle the right end cylinder to get at it for timing, no point in dismantling/remantling/dismantling it an extra time (is remantling a word? Means putting pieces back together, or it means putting a shelf over the fireplace... Anyway.)

 

[crueby]

Started milling out the slide links for the reverse gear today. In the book, Kozo mills all three links out of one long piece of stainless steel - I dont have any that wide/long, so made up a holding jig for the individual pieces. The jig is a chunk of aluminum bar with holes drilled/tapped for the two mount holes at the bottom of the links, plus two more temporary holes at the top of the stock. All three links were first drilled for these holes (started at same spot, counted off turns of the handwheels to get to the rest of the holes, returned to starting point for next piece). Then, using the same sequence, drilled/tapped the jig bar for the hold down screws.

With the first piece bolted down to the jig, and the jog held in the 4-jaw chuck on the rotary table, spent some time getting the jig and rotary table all centered up and the stock the correct distance out from the center - the two bottom screws were the reference points. Then, cranked out the distance from the pivot to the center of the slot in the link, drilled a starter hole for the mill, and milled the slot with several shallow passes.

Then, cranked out the distance for the top edge of the link (taking the radius of the mill into account), and drilled starter holes there.

And milled a slot - the bottom edge of the slot is the top edge of the final link piece. Ignore the extra hole above the slot - that one was a brain fart, fortunately in a spot that did not ruin the part!

Last milling operation on the jig was to do the short sections at the bottom corners of the link. The center part, between the mount screws, is not radiused, so that will be done later with the part held in the vise.

Sixth photo shows the state of the first link at that point, with the rest of the edges drawn on.

Last photo shows the link sawn out of the bar, ready for final trimming /shaping. The ends of the slot will get filed square too. One part down, two more to go before I take the jig setup down and start the final trimming...

 

[crueby]

Did the rest of the reverse gear link arcs this morning, and milled the shapes around the lower mount holes. Then filed the corners off and smoothed the ends.

Last step was to drill/tap the mount holes for the bracket that will connect to the reversing lever.

Next photo shows the complete links.

Last photo shows a link held in place on the engine.

Next step will be to make the spacer and slider piece that sits inside the link, and the threaded pin that holds it in place...

 

[SilverSanJuan]

The scale thumb in the last picture is really helpful to get a sense of how small these parts are. They look great. Was it difficult to thread those small holes? What stainless are you making these parts from?

Todd

 

[crueby]

The scale thumb in the last picture is really helpful to get a sense of how small these parts are. They look great. Was it difficult to thread those small holes? What stainless are you making these parts from?

Todd

I should carve a huge thumb to put in pictures to make parts look super small?

I am using 303 stainless, which is an easy machining alloy. As long as I use a little cutting fluid it works very nicely, easier than the bronze which gets grabby when drilling, a little harder than c360 brass (lighter cuts work best). I have used other stainless alloys in the past that were really hard, like this stuff (303 is what Kozo calls for). I've also used water hardening steel on some projects, that is nice to work with too.

 

[SilverSanJuan]

Thanks. I've only turned some 303 stainless on my lathe. That was pretty nice. So, I was curious as to how easily it tapped. I know what you mean with the bronze. It gave me fits while trying to ream a hole to size on my A3 tender's wheel bushings.

Todd