How big a motor does it take to do the job?

[whitney]

The bottom line really is how big a motor does it take to do the job? I have built the JGRO table design (rotozip router) and I plan to build the driver and controller around the motor; to do it the other way around doesn’t seem to make much sense to me. I have been doing some research on steppers: bipolar vs. uniopolar, half winding, whole winding, series and parallel wired. I am leaning towards a bipolar motor configuration with a current sensing resistor driver (L297/298) as opposed to unipolar motor with the same type configuration. I believe this would make better use of the power supply and be more efficient than a unipolar motor wired in bipolar configuration; ohms law really makes some tough choices for a DIY project. I want to maximize the (sweet rpm range) motor torque and efficency but am having difficulty deciding "how big a motor". I plan on using the router for light sign work, wooden clock gears and one off cut outs like yard ornaments or wirligig patterns. Also some plans for a few patterns of some "Gingery" projects I've been putting off.

Any input is greatly appreciated.

Whitney

[ViperTX]

Well....are you driving what type of leadscrew? Basically, just about anything in the over 200 oz-in torque as a stepper will work just fine.....

[whitney]

The plans call for 1/4-20 all thread, however since the bearings i already have will accept 5/16 with no modifications I will be using the standard 5/16-18 threaded rod.