If you look closely at the gearbox picture you will see a hose clamp around a cylinder in front of the fisher/drill motor. Andy Baker showed me this really neat sub-assembly. It takes the first reduction out of the drill gearbox and uses it to reduce the fisher or drill motor speed to near CIM motor output. Of course you need to put a drill gear on the fisher motor and there is an adapter to compensate for the difference in motor OD. All in all a very nice design that puts the two motors on the same side.
I think I have this essentially correct and am looking forward for the white paper on this. I can envision all sorts of mechansims that could use this subassembly
