Building Kozo's New Shay locomotive

[SilverSanJuan]

Thanks for that. I'll look in to getting some diamond plates.

 

[crueby]

On to the crosshead guides. These frames connect the cylinders down to the crankcase, guide the crossheads, and hold the slides for the valves. So far I've gotten the main tube portion done, lots more to go on them....

Started out with some large brass bar stock (stress relieved since they will be milled out to open-frame columns in the middle) in the lathe, held up with the steady rest. I squared up both ends, measured the lengths, and figured out how much more to take off one end to get them down to final length.

Then back in the lathe, took off that much, and drilled a starter hole, and bored them out to size (matches the cylinder bores).

Once all were the right length and bored to size, took off the steady rest and inserted one end of the jig used for drilling the cylinders - made a handy piece to hold the end of the live center to steady up the piece for taking it down to final diameter.

I did one end, flipped it end for end, and did the other.

Fifth photo shows one down to outside size, one on right still to go. Note that they are stamped for which cylinder they go with - I like to keep them in sets, in case there is any fine fitting/tweaking needed, they will be taken apart/put together a bunch of times during the build.

Next photo shows drilling the mounting holes, using the same drill jig from the cylinders. Same goes at both ends - same pattern used for the crankcase end. The lines down the center are to align the top/bottom holes with each other.

Last photo shows progress so far. The middle one has some guide lines on it, am figuring out the milling needed for the next step which turns them into open columns...

 

[crueby]

Been a productive morning - got the rest of the crosshead guides machined out. Last time I had them to diameter and bored through the center, this time set up in the mill and took out the center section on each side, leaving two 'columns' holding the rings at either end. The first operation had it set up in the vise, using the screw holes at the end to get it level - was a good double check when the mill broke through the screw holes evenly all the way around while taking down the surface.

After the first side was done, put in a couple of square bars as a reference, so that the second side would get milled parallel to the first, and milled out the same amount. That left a 10mm thick column on either side.

Then, set it up with the columns held between spacers, and milled the sides of the columns flat.

The tops of the columns got a small recessed rectangle - this is not used for any fittings, but makes it look like the original castings. Below the recess will be a fitting for the reverse gear.

Last step was to drill/tap a number of holes for mounting fittings for reverse gear and valve guides.

Last three photos show the engine parts so far test assembled (sure it will be apart/together again many times before it is all done). Really looking like an engine now. The bottoms of the columns get bolted to the crankcase, which comes next in the build. That part is built up from a bunch of pieces, should be interesting to do. For now, time to sit and stare at the shiny pieces so far! *beer*

 

[fuzzymuff]

Hi crueby.
This is looking fantastic. I have ordered a copy of Kozo's Shay book. You have inspired me to build a Loco.
Graham

 

[crueby]

Hi crueby.
This is looking fantastic. I have ordered a copy of Kozo's Shay book. You have inspired me to build a Loco.
Graham

Excellent! Welcome to the fun. It looks daunting at first but its just a lot of little assemblies. Hope you post your progress.

 

[crueby]

Today was a stock prep day - the crankcase is made up of 4 thick blocks, an angled top plate, and two side plates. All are non-stock widths, so had to mill down the next size up.

In the first photo, I had the two side plates milled to length, and was taking them down a few mm's to the planned width.

Then, milled the top plate to length, and needed to take the sides down a little and also angle them to 11.3 degrees. This is the angle of the sides of the finished crankcase. To put on the angle, I got out the handy tilt table, mounted the vise on it, and took down the edges with the mill.

Third photo shows an end view of the top plate with the edges beveled. I left the tilt table set to the angle, since the same angle will get milled into the blocks later, and leaving it set I could be sure to be able to duplicate it again.

Next up was to mill down the blocks to dimension - had to take off a little in all dimensions for this.

Last photo shows the parts so far. Still need to angle the sides of the blocks and put a step in them for the side plates to sit in. Then they will all be screwed together for silver soldering and further milling.

Thats enough for today - back at it tomorrow or the next day, got some work to do on the submarine for next RC gathering....

 

[crueby]

Cranking along - got the pieces for the crankcase fitted up today. Started out by taking the thick blocks and drilling a hole down each side for an alignment pin in a portion that will be milled off later. The pins were a push fit, so they would hold all four blocks in position so I could mill the profile of all together (this is Kozo's method, I can't take credit for it!). To get the holes in the same place in all the blocks, I set up the mill vise for the first one, with the block aligned with a straightedge on the side of the vise, locked down the table, and drilled each block one by one. Then set up for the other hole, and did the same process. They all fit together well, with just a tiny variation from one to the next. Kozo allows for this in his process by leaving the blocks a millimeter oversize to this point. I then used the fly cutter to smooth off the top/bottom of the block set, taking them down to final thickness. In the first photo you can see the pins in the blocks at the lower left/right corners.

Next up, got out the tilt table again (still set at the 11.3 degree angle from milling the bevel on the top plate edges), and clamped in the stack of blocks for milling the sides. This recess will hold the side plate on either side of the crankcase. You can see in the second photo the outline drawn on the side of the block of where the milling will go - this was mainly as a double-check that I had the blocks set right way up in the vise each time, the actual milling was done to measured depths not to the lines.

Third photo shows the first step milled in. You can see where the alignment pins are at the top/bottom corners at the front. After this step I turned the blocks over and milled the step on the other side.

Once both the steps were milled in, it was time to mill off the areas with the pins, forming the shoulders that will be at the bottom of the crankcase, level with the side plates. As you can see in the fourth photo I held the blocks with a machinist clamp for this process to make sure the blocks could not shift. This completed the shaping for the blocks.

Fifth photo shows all four blocks set in place to check that the tapered sides matched up with the tapered edges of the top plate.

Then it was time to fasten the blocks to the top plate to hold them in place for silver soldering. I measured out and clamped the end blocks in place for drilling/tapping some temporary screw holes - took some careful fiddling to get them both square to the plate and lined up flush with the beveled edge of the top plate.

Seventh photo shows the assembly with the side plates also drilled/tapped/screwed in place. The side plates were much easier to align, since the four blocks were already held by the top plate.

Last photo shows the engine sitting on the crankcase to double-check the spacing. Next step will be to silver solder up all the joints in the crankcase and then cut/file off flush all the screw heads.

At this stage, you can get a feel for how the full engine will look, even though there are still several dozen more parts to make.

 

[SilverSanJuan]

That's a big hunk of brass. It's really looking like an engine now. Great work!

Todd

 

[crueby]

This morning I braved the cold and went out and got the crankcase frame silver soldered up (going to be really nasty out next couple days, so wanted to get it done before the storm rolls in - we are going to get the north side of the one rolling through Chicago on its way to NY and Boston). Once it was all soldered up it went on the mill to true up the top/bottom surfaces and take them to final size. There was a slight warp (few thou) that the heating introduced, this took that out again. It was bolted directly to the mill table with bolts/t-nuts through holes in the top plate (in places where the plate will be bored out for the con-rods later). Since the t-nuts on a Sherline stick up above the table slightly (silly design) I had to put in some bars to raise it up - those are visible at the bottom of the crankcase.

In the second photo I have laid out the openings in the sides of the case, and am milling them out. The angled sides are stepped at this point, they will be smoothed out two photos down...

Next I mounted it in the vise, and milled the small flat at the top corners.

Last step in this session was to angle the vise so I could smooth out the angled sides on the openings with a small mill.

Fifth photo shows the crankcase progress so far.

That finishes up the current steps - more shaping/drilling next time, when the bearing caps are made and fitted. Last photo is the money shot, with the engine sitting on the crankcase...

 

[BAH101]

Try these from A2Z: http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={18DCA0E7-5B5D-4106-AD83-9597A4B4F209}&ProductID=3834&Category=TNut:Sherline

I have them and they sit below the table.

 

[crueby]

Try these from A2Z: http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={18DCA0E7-5B5D-4106-AD83-9597A4B4F209}&ProductID=3834&Category=TNut:Sherline

I have them and they sit below the table.

I think I have one that came with the quick change tool post from a2z, have to see if I have any more. Forgot about those! Thanks!

 

[crueby]

On to the bearing caps for the crankcase. Started with a piece of rectangular brass bar, milled it down to dimensions with it left long enough to get the four caps out. Then, set it up in the vise with the top edge sticking out and milled out the flats on either end of the caps.

Switched over to the drill chuck, and drilled out the mount holes (2-56 tap size). These will get opened up to 2-56 clearance later, for now they will act as drill guides for the holes in the case. I stamped each one with a number to match the posts on the crankcase, in case there were any differences cap to cap, and sawed them apart. No need to mill the ends square, that will be done after they are in place.

Then marked centerlines on the crankcase, and one by one clamped them in place and used them as drill guides to drill the holes in the posts. After that, tapped each hole to 2-56.

With all the holes tapped, it was time to go back and open up the holes in the caps to the clearance size.

Last operation was to bolt all the caps in place, nice and tight, and with the crankcase bolted to the mill table again it was time to take all the caps/posts down to final dimensions. Got it squared up on the table, and first milled off the ends of the caps even with the edges of the posts. Then, took a light cut on the end of the case - that surface acts as a measuring point to all the rest of the sides. After zeroing the handwheel at that setting, cranked out to each of the other posts and did the corresponding side. The posts were all left about a millimeter thicker than needed, to allow for any variance during soldering them up. Again, this is Kozo's method, I did not think this up myself - worked like a charm.

With the right sides of the posts all done, I went back and took the left side of the first post down to thickness, and used that point as the start to crank over to each of the others.

Next photo shows the crankcase sitting under the engine to show current state - one thing that I am going to do beyond what Kozo shows is to mill in a small flange around all the lower openings. I saw that flange on the real trains down at Cass WV, and I think that little detail will look good on the model too. Will do that after the rest of the machining on the crankcase.

The next step is a biggie - drilling for the main bearings for the crankshaft. The last photo shows how I am setting this up, on the mill with the crankcase bolted to the tilt table (drilled/tapped an extra set of holes in the table to match the holes in the crankcase).

The mill column is JUST tall enough for the drill to fit - glad I went for the taller column a couple years ago. Kozo did this operation on the lathe with an angle bracket to hold the case - my Sherline is just not big enough to do it that way, so I will use the mill. Going to have to make an extension for the center drill, and spend some time to ensure everything is squared up properly. That will be tomorrow probably - want to start fresh in the morning, one goof and the case is scrap.

 

[crueby]

This morning I got the setup for the crankcase bearing drilling all squared up, and made an extension for the center drill. The extension allows me to center drill each bearing post, drill it out, and center drill the next, to keep from wandering down the length of the crankcase. Kozo drilled out with a large drill all at once, I have found that I get better results if I drill with about a 1/4", and open it up with a series to 3/8" - reduces the chatter and irregular hole shape at the tops of the holes. The first three photos show the sequence of center drill, main drilling, and reaming to final size.





The fourth photo shows the crankcase with all the holes drilled through. These holes will hold bronze bearings, with a 5/16" main shaft.

With that operation done (phew!) it was time to drill the mount holes to hold the crosshead guides. Once again, the same drill jig made for the cylinder caps originally was used to locate the holes. As he points out in the book, this makes a total of 84 holes located with this one jig - well worth making it since it made drilling the holes very quick and accurate.

Last two photos show the engine parts so far test fitted together and assembled on the loco. At this point I am using socket head screws for easy assembly/dissasembly during construction. Final assembly will use hex head screws.



Good progress for this morning - next up will be to mill the conrod/valve rod holes in the crankcase, as well as lubrication holes for the bearings. After that I will add the flange shapes to the edges of the case....

 

[dalem9]

Such wonderful work . You can be proud of yourself .Really enjoy your work. Thanks for sharing .

 

[SilverSanJuan]

Wow... that was a nail biter for sure. Excellent work!

Todd

 

[Swifty]

Excellent work, it's all looking great as it comes together. I'm following along with my copy of the plans/book.

Paul.

 

[crueby]

Down the home stretch on the crankcase. Set it up in the tilt table again, at 40 degrees, at bored for the oil fittings that run down to the crankshaft bearings. Started with a mill to get a flat spot for the drill to start,

and switched to the drill to make the holes. A smaller drill went all the way through to the bearing holes. A set of rods with holes down the center will be added in a couple steps, below.

Next up, bolted it back on the mill table and milled out the holes for the con-rods and, for the middle cylinder, the valve eccentric opening. As the holes were bored out, the bolts were moved to make room for the next hole to be milled.

Last milling operation was to back bevel the sides to give clearance for the valve eccentrics and the con-rod bearings. Nice that Kozo gives the dimensions for these cuts, saves trial and error later on.

Last two photos shows the complete crankcase. The oil tubes are in place (loctited in), plus I took it up to the other shop and got the front face shaped back a little around the openings on the front, to put in the flanges at the openings that the real ones have. Small detail but I think it will show off the shape better once it is painted. I used a diamond grit dental bit in a high speed air tool (about 450,000 rpm) that made short work of it. A little sanding to smooth it out, and also rounded the upper edges where the sides go into the top.



Next up will be the bronze bearings, then on to the crankshaft itself!

 

[SilverSanJuan]

Very nice. And, the detail you added to the edges of the crank case really does look good. Nice touch.

Todd

 

[crueby]

Back in the shop this morning, and got a start on the crankshaft bearings. They are made from bronze, and are shaped like a spool to fit in the crankcase posts/caps. Started out with a bronze bar a few sizes larger than the bearings will be, to leave room to split it lengthwise. First, milled flats on two sides to make it possible to grip the two halves in the vise later.

Then, hacksawed (hacksawned? hacksawnded? Cut!) down the center of the bar, and milled the inside surface of both halves back flat again (used a parallel bar underneath so the new flat would be parallel to the outside).

The two halves were then soft soldered back together again, and the outside flats given a light pass in the mill to even them out - could not get them perfectly aligned when soldering. The bar was then cut into two shorter pieces so it would not stick too far out of the chuck. Each piece is long enough to get out two bearings while leaving enough to hold in the chuck.

So, chucked up the first piece in the 4-jaw, and kept adjusting till the solder line down the end crossed the center point of rotation, and drilled/bored out the center to the size of the crankshaft. Kozo recomends boring the hole vs drilling/reaming, since the reamer would tend to force the halves apart. I believe it, since when I drilled the starter hold for boring it did crack the solder joint, had to clamp/reheat it to get it back together again.

After boring the center out, switched to the parting tool to nibble out the center section of the outside to form the spool shape - the flange at either end will fit over the crankcase posts/caps. When that was down to size, and just wide enough for the cap to fit down over it, the bearing was parted off.

Next photo shows the two halves of the bearing test fit in the cap and a piece of the rod for the crankshaft. You can see how it overlaps the sides of the cap, and also how thin the bearing is.

Last photo shows the first bearing in place on the crankcase. One down, 3 more to go....

 

[crueby]

Got the rest of the crankshaft bearings done. One thing I changed after the first one was to drill the starter hole for boring with the soldered-together halves all the way into the chuck, to keep the drill from cracking them apart. After starter drilling, I then moved it out like I showed in the first one and bored the center and turned the outside. Doing it that way kept the parts together till I parted them off. First photo shows the bearings all in place and test fitted with a piece of the stock for the crankshaft.

With everything fitting fine (a little tight to turn, close enough that I will wait till the crankshaft is done and will lap them with some diamond paste to a nice smooth run), it was time to loctite the bearing halves in place. Being careful to keep the pairs together and oriented the same as they were made, a drop of loctite went in between the bronze bearing and the brass case. The caps were screwed back on to press everything into place, with a piece of card stock between the halves to keep from sticking everything together. After it set up, the card stock was removed.

Last two photos show the engine so far bolted up on the loco. This morning I made the lower bracket, which holds the crankcase steady to the frame of the loco. It is a piece of brass sheet stock, bent to shape (another template was made to get the angles) and drilled for three mounting bolts top and bottom. You can see the plate behind the crankcase in the photos (shows best in the last one).



This was the last step before making the crankshaft itself. It will be a built-up crank rather than turned from one solid bar. I have had great luck making them that way on other engines, going to do the same here. I make the webs and eccentrics as press fit on the rods, position everything and drill for cross pins at every joint, then for good measure go back with low temp silver solder to fill in the joints and lock everything together so nothing can wiggle loose. As long as the web pairs are made together and kept oriented right, the final results come out square. Going to take some time and select stock and lay out everything, then will get a start on it - should be fun!