[Andy A.]

What ever value you (or someone else comes up with), don't design around it. As the worm and gear wear in, they are going to become a little sloppy, and this could change the nature of the backdrive.

For what it's worth, with a pair of vicegrips on the output shaft, I can just drive the motor with my hands. Figure a 6 inch leaver arm and all the force a 20 year old guy can muster with his right arm. Once I get it moving, the force needed goes way down.

Maybe I'll bring a torque wrench with me tomarrow and see if I can rig something up quickly on an old motor.

-Andy A.