Geared stepper motor as a 4th axis?

[HereinCS]

I'm building a tiny cnc router and would like to consider a 4th axis. Can I use a geared stepper motor as a 4th axis? I'd make some sort of clamp to hold the material only the shaft.

[jsheerin]

Probably not a good idea... You would probably kill the bearings in the gear box eventually. Better would be to setup a shaft with some radial and thrust bearings, mount some kind of chuck to it, and then drive the other end of the shaft with the motor. If you do a search in this forum you should be able to find plenty of examples.

[simpson36]

Check this out for a belt reduction 4th axis:

[nomedia="http://www.youtube.com/watch?v=sC2urdg_bqg"]YouTube- New Super Duty 4th Axis Rotary Engraving on mini-machining center[/nomedia]