1. For the main frame, I see Dave and others weld the frames in addition to tightening with screws. Is it a must for welding? Locally, we need a license to weld! (which we obviously lack as students)
2. About the motor. I have a motor as belows, planning to reduce its speed with reducer. The power should not be a problem. But:
(a) How can I couple this shaft to a worm? How exactly do people call these shafts with a notch?
Ans: They are called keys and keyways. Keyway couplers serve the purpose well.
(b) Is it a monophase or triphase motor?
Ans: This is a monophase motor because triphase ones don’t use capacitors and there are only two power connections in the wiring (U1 and U2).