Correction: Not 630 mm but .630 inches or 16 mm.

Boake

Thanks for the input.  The upper half of the frame  will have to be milled and possibly the lower half also.  I am considering flywheells from NWSL that are 630 mm diameter and a slip fit on a 2mm motor shaft.  Do you know the ball diameter on the GP50 drive shaft?  I am also considering using one of their universal couplings if I can determine the dimensions of the ball.

Boake

Does anyone know the diameter of the motor shaft of Bachmann motor H61206 used in the HO GP50 engine.  Any info on adding flywheels is also appreciated.