"Bob in Phx" wrote: (clip) any other ideas.... (clip)
^^^^^^^^^^^^^^^^^
Drill endwise into the interface between the shaft and the gear, so you have
a round keyway, in effect. Then run a tapered reamer down this "keyway,"
and drive in a taper pin. Since it looks like the shaft sticks through the
gear, you will have to place a collar over the shaft, so the drill can be
positioned properly half way into the shaft and half way on the gear.