Lathe mandrel clamp.

[kquiggle]

I agree that the "keep it simple" approach is a good one, and that is what I will do for my initial build.

The reason I asked about the cam action is that I am working on building an electronic dividing head (arduino powered) for cutting gears. For my initial build, I am not even going to include a spindle clamp, so I can see if the stepper motor has enough holding torque (probably not). However, I'm guessing that it is pretty likely that a spindle clamp will be needed, so I will make sure I can add one later. Similarly, although I will not initially build an automatic clamping mechanism, I want to make sure I can add one later if I want do, without having to do a complete re-build.

As for an automatic clamping mechanism, I was thinking of using a solenoid to activate the spindle clamp after each partial rotation. Right now I have all of the electronics (not including the solenoid) working, and I'm starting on the mandrel holding mechanism. Your posting came along at just the right time for me - previously I was searching the Internet for ideas, and coming up with nothing (searched on spindle lock, spindle clamp, mandrel lock, axle lock, shaft clamp, and numerous other variations and never came up with anything useful).