Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Old Apple Imagewriter II dot matrix printers have a NEMA 23 motor,
rated at 5V (forgot what the current is) and via a balance I tested
several to 60oz-in holding torque. So I've been collecting cheap and
free Imagewriter II printers...

They also have a nice 28V transformer at several amps, great to drive
these motors with resistive or PWM current limiting for better torque
at speed.

I think Stefan asked about using two steppers to move an axis or using
a belt/gear to couple both sides. I'd use two steppers, as you get a
lot more torque. Otherwise you may find most of your torque eaten up
in moving two screws. And these little buggers are certainly cheap
enough if you look.

However, you do have to worry about the possibility of one side
skipping a step if the load is too high, and then causing binding.
Shouldn't be a problem with a drill only machine.

Steve Greenfield