Fabricating Insulating Universals for Brass Shays & New Motor Install

A California Western Locomotive and Car Rebuild Shops Project


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What is that they say about necessity is the mother of invention! That applies to this project. Some time ago I purchased this PFM Pacific Coast three truck Shay with a missing universal component that connects between the second and third truck to drive the wheels in the third truck.

The mechanical pencil is pointing to where the missing component should be located. I checked around with various sources but was unable to find replacement parts. In the past I have manufactured similar components out of brass but in this case there is a difference in polarity between the third and second truck on this Shay so this universal component had to be plastic or some electrical insulating material. In addition to this project I also had a Key three truck Shay in the shops that is in need of all the universal components for the entire drive line.

The other day I was looking at the shape of an old plastic dummy coupler in my parts drawer and I realized that with a little work with files and sand paper I might be able to get it into the shape of the male component with yoke that I needed for the Shay. The challenge was to remove equal amounts from the various surfaces during the carving and sanding process in order to keep the shaft centered on the carved and shaped yoke. This image shows the rough shape of the carved and sanded shaft and yoke when compared to the type of plastic coupler I started with.

I also had to make sure not to remove too much material from the yoke portion so it would be capable of handling the torque applied by the drive line. Before getting the yoke to final shape I used my pin vise to carefully hand drill a #68 hole to accommodate the pivot pin before completing the final sanding. This image shows the male universal component in place and functioning.

It took about an hour to carefully carve, shape and repeatedly test fit this part to it’s final configuration. Upon completion of shaping this component I found a smaller coupler from an HOn3 kit which I will use for the next carving session because it will require removal of less material to achieve the final shape I need. This image shows the relationship of the HO coupler on the top with the smaller HOn3 coupler and a rough cut universal made from the HOn3 coupler and a similar component I made out of brass a few months ago.

With the coupling issues resolved I start to look at can motors to replace the original open frame motor. While the original open frame motor provides better than expected operation starting the locomotive at 4 volts and 3 tenths of an amp, I hope to get better operation from a can motor. These are two of the candidates for this project. A NWSL 1630 and my favorite 8900 rpm flat can motor.

The NWSL motor shaft is just slightly too short which would require the motor to be inside the tubular part of the boiler/firebox. In this position it sticks down too far and the frame will not fit up snug.

The shaft on the 8900 rpm motor is way too short. Drats!

Rummaging around I find one of the old, first edition Sagami 1630 motors that were sold back in the 1970’s by NWSL. The shaft is perfect and contrary to my normal mounting I may be able to use the original mounting bracket. Note where the front of the original motor is in relation to the cylinders.

About fifteen minutes later, most of which was used getting the burrs off the NWSL bushings I used to facilitate using the 2.4mm id original worm on the new 2.0mm motor shaft, this is how the old Sagami sits on the frame. Note where the new motor is in relation to the cylinders.

This shows how the new motor is mounted to the original motor mount. I did put a dab of my Silicone glue under the motor just for kicks and to provide additional mounting security.

The mechanical issues have been corrected and th emodel is now ready for paint and further detailing. At this time the model starts with 2.5 volts and about 1 tenth of an amp. Again, this is without lubrication of the gears and mechanism. It should run better after the model is painted and the mechanism broken in and properly lubed.


Fabricating Insulating Universals for Brass Shays & New Motor Install

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