Question about new digital stepper controllers

[irving2008]

Nice. Is that a steel bolt you are using as a cutter? and letting the ali gear wheel free rotate? Only issue that would worry me is how much torque you can put through the final piece, its a fine thread and not much contact area.

[Jonathan]

Yes, it's just a piece of steel M12 threaded rod that I hardened a bit and ground slots into to encourage it to cut instead of rub, although it does work without doing that. The gear wheel does rotate freely in the toolpost. I should have used a coarser thread since, as you say, the torque is limited otherwise. This gear is part of the mechanism to control the pitch of the blades in the wind turbine I made, so I chose to use a worm drive for the same reasons I gave earlier - it means I can reduce the current supplied to the motor significantly when stationary to save power. I then made the worm gear, which is just an M12 thread, from brass, which I know is not the best material but better than steel:



It's probably easier to just use a 4" rotary table. How much backlash do you get with yours?

[irving2008]

...It's probably easier to just use a 4" rotary table. How much backlash do you get with yours?

Of the top of my head I think it was around .07 - .08mm, mainly in the in/out motion of the main shaft rather than the gear meshing itself. Not great but usable and a lot better than the stock table had. There were some lightly loaded Bellevue washers in there but making it too tight meant the motor struggled. I had planned one day to up the motor to a higher spec but I dont use it enough to justify the spend and it was good enough for the purpose I needed.