I have delusions of slowing down my Grizzly (grinder). I've been reading about mounting a sheave on the motor shaft and running that to a separate motor. That sounds reasonable has anyone done something like this? I need a 1" ID for the existing motor shaft but what OD? I don't want it to go faster so what sizes should I use as far as OD goes on the motor? I'm sure figuring out involves math and I suck at that so I'm asking. 