Building Kozo's New Shay locomotive

[Roger B]

Your other hobby work is absolutely magnificent    Not long to go on the Shay engine   

[crueby]

Last step to do on the crank web pieces was to radius the ends. To do this, I made an arbor by turning a shoulder on the end of a bit of brass bar the same diameter as the crankshafts, and threaded the end for a bolt. Then, with a pair of the webs bolted on the shart, turned the radius on one end, swapped to the other hole, and did the other end. This also took the webs to final length. (photo 1)

Second photo shows the first pair turned (on the right), second pair (on the left) still in rough length and ready for thier turn.

After that, on to the eccentric cams. Started with a piece of stainless rod, and turned the shoulder for the eccentric follower on the end, and parted it off. (photo 3)

Next photo (4) shows the cam blanks with the web pieces.

Last operation on the eccentrics was to offset drill the eccentrics. I wound up having to make an extra set, since I tried using the 4-jaw chuck to offset drill, but with such a small part it was too hard to measure the offset accurately and I wound up going through the side of the first ones. So, went another direction and clamped the 3-jaw to the mill table (have a chuck-thread-to-t-slot adapter), centered up the piece with the center drill, and cranked over to one side the offset distance, and locked it all down. Then I could drill all 6 of the eccentrics with that setting, wound up being a quicker way to do it than in the lathe. (photo 5)

Next two photos show drilling/reaming the hole in the eccentric.

Last photo shows the first pair test fit on the crank shaft - all looked fine, so went ahead and drilled the rest of them...

[crueby]

On to an exciting step - assembling the crankshaft. I started out by making sub-assemblies out of the cranks and eccentrics. The cranks were easy - ran a piece of rod the right length for the crank pins through the webs, a longer piece through the other hole, and drilled through the webs and rod for some drive fit pins. Since I have been keeping the web pairs together and oriented the same through the whole process, they lined up nice and straight. (picture 1)

Second photo shows the web pieces all pinned.

Next up was to make subassemblies out of the eccentric discs. Each pair sits back to back on the main rod, with a 19.5 degree offset from centerline for each one. I laid that out on card stock, and used that as a pattern to clamp up the pairs. Then drilled for a cross pin to hold the two discs together. (photo 3)

Once I had all the webs and discs ready, it was time to put it all together. Lots of measuring, checking, more measuring, rechecking the book, .... Once I had the main rod turned to length with shoulders at the ends for the u-joints, and marked out for position of the pieces, I pushed on the first crank web to its position, and drilled/pinned it in place. Then set up the rotary table vertically, with a tailstock to support the other end of the shaft, and zeroed the table with the first pinned web square to the table. You can see on the shaft that all the webs are in position and roughly to right angle (120 degrees to each other). There is also one eccentric pair in place - the others go on later at the ends, no need to put them on now. The middle eccentric will be drilled/pinned later. (photo 4)

With everything aligned and zeroed, I then turned the rotary table 120 degrees for the next web, and clamped the web in the mill vise. This squared the web to the table, holding it in place for drilling. One of the webs was drilled/reamed, and a pin tapped in far enough to hold it, and the second web was then drilled/reamed/pinned. The pins were not driven home yet, I waited till it was off the mill to do that so I would not risk bending the shaft. (photo 5)

Then, turned the rotary table another 120 degrees and did likewise for the third web pair. With all the webs drilled and pins started, I took it off the mill and with each web sitting on the anvil tapped the pins home and filed them off flush. The middle eccentric is not drilled yet, wanted to check everything with the crankcase first. (photo 6)

Next photo shows the crank so far sitting on the bearings in the crankcase. It is a nice smooth fit, so all has gone good so far.

Last photo shows the bearing caps screwed on to make sure it still fits right - it does. I also slipped on the outside eccentrics to check that the shoulders at the ends were the right distance out.

Enough for today, time to walk away before getting tired and pulling a brain-fart on it.   

Next step will be to mark the positions of the eccentrics and drill/pin them. Each one needs to be at the proper angle to the corresponding web, so I will figure out a jig to hold the discs, with the web they go with clamped in the mill vise. After that is done, I will lap in the shaft on the bearings - it is a good fit, just a tiny bit tight, so the lapping should work out well. I have some of the time-saver compound that someone else recommended, will try that out on it.

[ths]

That looks good Chris, and an interesting arrangement with the eccentrics, all outboard like! Hugh.

[crueby]

That looks good Chris, and an interesting arrangement with the eccentrics, all outboard like! Hugh.

Thats how Kozo designed it, one set inboard and two outboard. Should be an interesting visual when its all going! It also kept the crankcase just short enough to drill with a standard length drill. I had to finish drilling with the bit only 1/4" into the chuck, but that was enough.

[b.lindsey]

Nice work on what could be a tricky part Chris. It looks great!!

Bill

[crueby]

Quick update - got the eccentrics drilled/pinned on. Turned out no jig was needed since I already had each pair pinned at the correct angle within the pair, just clamped the corresponding webs in the vise, and the eccentrics self-aligned on the tops of the jaws (checked several times that I had them the right way round, they are not perpendicular to the webs but 19.5 degrees off that). Started with the center set, and clamped the eccentric in place with a spacer from the next web to get it located properly. (photo 1)

Second photo shows doing one of the end sets.

Last photo shows the crankshaft so far. With all the parts pinned in place, I went in with some low temp silver solder and flowed that into all the joints to lock everything in place, and keep any pins from working loose. The pins are doing the work of holding things in place against rotational forces, not the solder.

All that is left on the crank is to get it lapped into the bearings and cut away the parts of the main shaft within each web set. Next up is the universal joint sets that run out to the drive shafts on the trucks. Interesting part on Shays, the u-joints include a square shaft section the telescopes as the trucks pivot.

[fumopuc]

Hi Chris, magnificent. Waiting on the exciting moment now, when you will start to cut of the not needed sections of the shaft.

[crueby]

Hi Chris, magnificent. Waiting on the exciting moment now, when you will start to cut of the not needed sections of the shaft.

That always SHOULD be a good moment - never had a problem making the cranks that way before. As long as I cut in the right place....! I did get those pieces cut out this morning, and the hacksawn sides cleaned up with the mill. No movement at all in the shape of the crank, still sits nice and flat in the bearings. 

Just needs a little polishing up to make it look shiny again. The lapping compound should be here Monday according to the tracking info, will lap the bearings then. In the meantime I am going on with the universal joint shafts.

[Tennessee Whiskey]

Well while you are waiting on the lapping compound,  can you knock me out a real pretty bateau?    I am really enjoying the build 

Cletus

[crueby]

Well while you are waiting on the lapping compound,  can you knock me out a real pretty bateau?    I am really enjoying the build 

Cletus

I've built a dozen or so boats, everything from solo canoes to 18' gaff rig sailboats, so you fund it I'll build it! May take more than till monday though! Need a REALLY big box and a ton of packing peanuts....!

[daveb]

Hi Chris, really enjoying your build.  I wish you did the crank a year ago.  I would have used your method rather than Kozo's single piece.  It took me four tries to get the thing right.  At the rate you are going you will pass me soon which is good for me because I'm learning a lot from the way you work.  I have the engine running on 10#s +/- and have just started the cylinder cocks.  Keep up the good work and the great postings.

Picture 1  3 rejects
Picture 2  the one that works 

Dave

[crueby]

Hi Dave, glad the fourth one worked. The one piece method allows for no mistakes and a whole lot of deep interrupted cuts that I thinl would have been hard omn my little lathe. I did the built up cranks several times now and have had no trouble with any of them. Your engine running on 10 psi sounds great, there are a lot ov sliding parts to build up friction. Do you have any videos posted of it running? Love to see it go!

I never did an engine with the cylinder cocks, any leakage issues on them?

[daveb]

Hi Chris

I do have a video on Youtube but I don't no how to link to it.  It's Under "Kozo shay running on air"
I tried to attach here but it didn't like it.

This is the first project for me so I don't no about problems with the cylinder cocks.  I do have a couple Accucraft steamers with cylinder cocks with no problems.  For running the engine on air I just plugged the holes as you can see in the picture.  there's going to be a lot of little parts.  BTW the oiler piping calls for 2mm copper tubing, have you found a source for this?

[Jo]

<a href="https://www.youtube.com/watch?v=zVJP8lqDhDk" target="_blank">http://www.youtube.com/watch?v=zVJP8lqDhDk</a>

 

Jo