1-1/2" Scale Shay Under Construction

On the loading ramp, ready to go to a meet in Maine.


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3-cylinder shay
This Shay is based on the design by Kozo Hiraoka that appeared in Live Steam magazine. It has been built to twice the size of the original plans. This Shay has a 3 cylinder engine with Stephenson valve gear. The universal joints (one on the left side of the crankshaft, 5 more sitting on the cab floor above) are based on the design of Ken Schroeder's Shay.
The crankshaft was machined from a solid block of steel.
So far, I have not used any castings in the construction of this engine, parts have been either machined from the solid or built up by silver soldering smaller pieces together. The cylinder frames are a good example of the built-up construction. Similar to the original design, I changed to a two piece brass/steel assembly rather than cutting the part from one piece of brass pipe. The tilting table was built so that I could machine all four main bearing faces at once to be sure they are in the same plane.
reaming bearings
Here the cylinders and engine frame have been placed on the lathe cross slide for reaming. I didn't have a long enough reamer to go through all four bearings so I did the first 3 bearings, removed the front cylinder, and reamed the last bearing.
Engine close -up
Here's a closer look at the engine. Cylinders are cast iron, cylinder frames are made up of steel tube and brass bearing blocks. Connecting rods are steel, with square bronze bearings. Crossheads are bronze. Most of the valve linkage is stainless steel. The eccentric straps are bronze. All the valve linkage is bronze bushed.
Engine, another view
Another view of the engine showing the exhaust manifold leading forward. The three piston blanks are stacked in front of the engine on the running board. The piston rings will be made from 25% carbon filled Teflon (PTFE).The intake manifold is visible above the top of the cylinder heads, the brass block at the top of the manifold is the 3 way steam branch. Steam oil will be injected just above this branch for cylinder/valve lubrication.
This view from the rear shows the valve linkage and a valve (bronze) located in the valve chest.
Engine Manifold
This view shows the exhaust/intake manifold. Pardon the oversize bolts, they're temporary until appropriate scale bolts are made.
More Parts
Shown here are the remaining gears, all modified and ready for mounting. The eccentric on the left hand side is for the lubricator pump. The pistons are on the far left. On the right is one of the spaces to go between the large gears and the wheels. This engine is designed to be converted from 7-1/4" to 7-1/2" gauge.