Over the years NorthWest Short Line (NWSL) has produced 3 quartering jigs. Each consisted of a central frame with axle slots and 2 nylon screws to secure the axle. A slot was provided for a gear. Two steel rods supported and aligned the pressing bars on which pressing pins were mounted. Crank pins were inserted into the driver for alignment in the VEE bars, which had flat hub pressing pins.
Essentially of excellent design, there are a few shortcomings. The gear slot is not wide enough to accept all gears. (ie. Bowser & Mantua plastic.) A thin flat mill file can widen it to accept them. In addition, none can handle cases with both offset double reduction gears and integral axle bearings. The metal ones provide an extra allowance of about .023" on each side.
The first, of aluminum, required a 2 step process. First the mounted driver was setup with the VEE bar and the axle was secured with the screws. Then the VEE bar was moved to the other side to setup the other driver. The integral pin on the flat bar was used to backup pressing directly on the mounted driver axle end.
Basically identical, the second used as second VEE bar, which eliminated bar reversing. The steps were essentially the same otherwise.
With an acetal plastic replacing the aluminum, the present unit is basically the same design as the second.
NOTE: Use shoulderless screws of the same thread as crankpins , long enough to clear jig, to reduce offset and provide consistency . Store with jig. 1-72 is the most common.
Due to the extended rods, pressing is done best with the corner of a machinist's vise. Final gauging can be done readily using the NMRA gauge.
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