View Full Version : How much leadscrew torque?

07-08-2007, 09:23 AM
Has anyone here measured or calculated the max torque needed to drive the leadscrew on a typical 12" bench type lathe? I'm thinking of hooking a servo drive to the lead screw on my lathe because I'm tired of (lazy about) changing the gears all the time.

07-08-2007, 09:27 AM
Engage the half nut and put a torque wrench on the leadscrew.

07-08-2007, 10:16 AM
Drive the leadscrew, or drive the carriage and tool while cutting?

07-08-2007, 10:40 AM
It doesn't take very much. I can't quantify it better than that but I put an electric leadscrew drive on my SB9 and used a small dc gearmotor to drive it and it has no trouble.

Here'a a link to info on mine including complete plans for a PWM drive.


I should add that I highly recommend such an accessory for a change gear lathe. I use it constantly. When roughing it is really nice to just crank in the feed rate with the knob until the lathe begins to grunt.