Hi all,

I need a sanity check with this.

I have an electric motor that runs at 3450 RPM. I want to attach it to a mandrel for buffing, but I need to drop the RPM of the buffing wheels to around 1200 RPM. So that's roughly 1/3 the speed.

I did some calculations on the pulley sizes using pi *D=C. A 2 inch pulley circumference is 6.28, and a 6 inch pulley is 18.85. So if my calculations are correct, and I put a 2 inch pulley on the motor, and a 6 inch pulley on the mandrel, that should give me a 1:3 ratio, or 1150 RPM.

Am I correct?

Your math is correct. You expect these pulleys to mesh like gears? How are you going to prevent slippage betwee them?

Your math is correct. You expect these pulleys to mesh like gears? How are you going to prevent slippage betwee them?

Oops, Sorry. I forgot to mention that there is a V belt between them.
And thanks for checking!