Can I offer a better solution than buying HF stuff? (their stores stink from the Chinese rubber smell).
You can buy a pair of pillow blocks and a shaft with the proper clamps to clamp the buff wheels. Add a
couple of pulleys and an appropriate motor, a belt and you can bolt it to a bench. Viola, you have a buffer.
Make sure you compensate for the pulley ratio if you do anything but a 1:1 ratio.