Building Kozo's New Shay locomotive

[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. (photo 1)

Once both sides were stepped in, the top was grooved down the center - the crosshead will rest on the two upper rails. (photo 2)

A simaler groove was cut in the bottom, to give estra clearance to the piston crosshead. (photo 3)

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. (photo 5)

Last step was to drill the mount holes to match the ones in the piston columns. (photo 6)

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.

[joe d]

Hi Crueby

Just popping up again to say that I'm still following along, and enjoying it 

You sure are showing some really nice work!

Looking forward to more,

Cheers, Joe

[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. (photo 1)

With each piece held in the vise, the sawn edge was taken down smooth with the mill. (photo 2)

Next photo shows the two strips after this shaping. (photo 3)

Last steps were to drill the mount holes, and saw the strips into the 6 retainers. (photo 4)

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]

Hi Crueby

Just popping up again to say that I'm still following along, and enjoying it 

You sure are showing some really nice work!

Looking forward to more,

Cheers, Joe

Thanks Joe!

[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. (photo 1)

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. (photo 2)

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. (photo 3)

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! (photo 4)

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. (photo 5)

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. (photo 1)

Last step was to drill/tap the mount holes for the bracket that will connect to the reversing lever. (photo 2)

Next photo (3) 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...

[Roger B]

Every day more splendid parts    Still following along and enjoying the build 

[crueby]

Every day more splendid parts    Still following along and enjoying the build 

Thanks! Another dozen parts, a few temporary fittings, and it will be ready to air power it first time! Can't wait!

[daveb]

Its a great feeling running on air

Dave

[crueby]

With the reverse gear links done, on to the fittings that go on them. First up is the little bronze sliders that ride in the slot. They are curved to match the slot, so the same jig that made the links was adapted to make a strip of the sliders - just had to widen it at the end with another bit of aluminum. Then the bronze was screwed down to it and adjusted to be the correct distance from the pivot point of the rotary table. (photo 1)

With all the adjusting done, a few passes with the mill cut the arc into the bronze. (photo 2)

After that, a set of holes was drilled spaced along the strip - this hole will take the pivot pin into the valve crosshead. The strip was long enough for 4 sliders, so have one spare if I cut wrong later. (photo 3)

Last step on the sliders was to cut them apart and to length. (photo 4)

Next up is a little bracket that bolts into the center of the links, and will hold a pin that connects the actuating lever to move the link between forward and reverse. This started out just like the retaining strips did a few posts back, as a piece of larger stainless rod, milled to size, then a slot milled down the center, and the side sawn off to leave an angle bracket shape. This sawn edge was cleaned up with the mill, and it was ready for the next step. (photo 5)

A set of holes was drilled/countersunk along one edge for the mounting screws, and the other side drilled for the pivot pin. (photo 6)

Last step was to angle the mill vise and angle cut the sides of the brackets. (photo7 )

Last photo shows the links, sliders, and brackets all assembled with each other. There will also be a little spacer piece between the slider and the crosshead, but I am going to wait till assembly time with the eccentrics so I can measure the lengths needed.

Next up will be the eccentric followers and connecting rods...

[b.lindsey]

Still following along Chris. Nice job on the links and associated parts. Its getting closer now!!

Bill

[ths]

Nice little production run there Chris. Bronze and steel? Your brass supplier will be getting nervous! Cheers, Hugh.

[crueby]

Nice little production run there Chris. Bronze and steel? Your brass supplier will be getting nervous! Cheers, Hugh.

They would, but its the same place, so they just like that I am using up stock!

[crueby]

Only got a few minutes in the shop today, got the pivot pins for the reverse gear links made. Like all the other engine steel parts they are 303 stainless. Started with a length of rod, turned just the end down to size for 2-56 threads - did not want too much hanging out and getting bent. (photo 1)

After threading the end, went back and took the shank down to size too. (photo 2) Parted it off, (photo 3) and reversed it in the chuck to trim the head to thickness. (photo 4)

Then, over to the mill to put the hex shape on the heads with the rotary table. (photos 5 and 6)

Last two photos show the completed link pins in place - they go through the sliders in the link and into the valve crosshead.

Probably get more shop time tomorrow, will get a start on the eccentric followers.