Axle drive
Last piece of the barrel
To "connect" the motor to the barrel axle, a PVC pipe cap, drilled and fitted with a 3/8" brass NPT pipe plug.
The square drive socket in the motor is metric. A 1/4" pipe plug was too small, and a 3/8" too big. Well, too big could be rectified!
Each side of the square head was filed down until it fit. Turned out to be @ 5/16" (@ 8mm).
This cap is just friction fit the the end of the axle tube.