Easy enough to figure out. Just figure the typical electric motor rpm should be somewhere in the low thousands- likely 1500 RPM or somewhere thereabouts (depending on the particular design- I've seen videos where you can hear a whining noise that would suggest more like 4-5000 rpm - the design obviously varies). Then look at the speed of the cutters - in some of these, it looks like maybe no more than , say, 10 rpm. So in that case the reduction gearing would be multiplying the initial motor torque by, say, 200 times. It varies. Some of these are capable of chewing up a car engine camshaft- which is hardened steel. Those are the most powerful ones, I think.