Inertia calc

I want to use a servo motor and a Gecko Drive to turn the lathe
spindle of my Shoptask, not as a permenant setup but as an
alternative drive when I want to cut threads using CNC. I have a 60
volt, 7.2 amp, 34 frame, 2300 rpm motor. (Very heavy piece of iron).
My question is:
If I use 10 to 1 timing belt pulleys, will this motor produce enough
starting and stopping torque to accomplish my purpose. Or as an
alternative should I rig a worm and worm gear drive. This of course
would be a much more difficult job.
I don't know the weight of the spindle assembly, but 20 pounds or
less would be a guess, and I wouldn't be using a heavy chuck, just a
collet closer. Spindle speed could be in the 50 to 200 rpm area.
Thanks for any input,
Jerry