[ShaneP]

We mount the fisher price transmissions which control our arms in a similar fashion.

The shaft they turn keeps them in place, locked up against the square tubing (in our case, 1.5"x1"). Shaft collars keep the transmissions from sliding out (off the shaft).

To turn the shaft (1/8" keyway shaft), we machine an octagon hub/block that picks up the octagon shape of the inside of the fisher price output. The hub is then bored to the shaft diameter and an 1/8" keyway is broached.

Hose clamps are used to hold the white plastic output of the fisher price transmission to the octagon hub to avoid slippage.