In the picture above you can see a prototype assembly of the parts I purchased. This new design offsets the shafts of the motor and rotator to avoid having to get perfect alignment and reduce binding. Initially I considered using a universal joint but they cost more than all the other parts put together and it’d be difficult to pair up the different diameter shafts.
Instead, to transfer the power from the motor shaft to the rotator shaft, I used gears with matched pitch, etc. The main rotator shaft is 1/2″ diameter and the motor shaft is 5/16″. The rotator shaft is held in place with mounted low-profile bearings. Everything is adjustable for fine tuning after assembly.
The motor is a geared, “high torque” motor (higher torque than the microwave motor I used in version 1). This motor is much better suited for this purpose but presents a few more design considerations. In trying to keep the design as small as possible I’ll have to fabricate a cowling for the motor.
The cowling will keep the electrical parts safely away from the user while allowing airflow to cool the motor. I’ll also mount the switch in the cowling so it’s accessible and easy to use. I’ll need to cover the gears to keep the user from getting fingers or clothing caught in them, too.
All-in-all it looks pretty good and I’m sure it’s functional at this point. Hopefully I’ll be pleased with the final results once I get the cowling, etc. completed.