? How fast to run a belt drive mandrel?

[Mark Gottesman]

Snagged one of those old belt drive grinding mandrels with the oil cups and bronze(?) bearings.
I have a 1725 rpm motor and want to figure out what speed these things will handle. Primarily going to use it for wire wheel and buffing work while cleaning up tools.

The wire wheels I get go to 4500 RPM and the stones to about 4200. Just wonder if I can spin those type of bearings that fast.

 

[DonDeJ]

I'll give you some things to think about, but I don't have a good answer. The faster you run it and the harder you work it, the quicker it will wear out. What condition are the bearings in? When you use a wire wheel, you can expect wires to come loose/break off occasionally, so a faster speed would shoot them at you faster. I've found them stuck in my clothes and skin after using them, so protect yourself. Slower speed with a buffing wheel works well. Again, buffing compound will fly off at you, the faster it spins, the faster it will hit you.

It will probably bog down more easily at lower speed. You really just need to try it. try using the same size pulley on the motor as the mandrel, giving you speed to match the motor. If it doesn't seem to work well enough at that speed, increase the motor pulley by 1/2", or whatever you want. Zinc die cast pulleys should work fine, and they aren't expensive.

Good luck with your experiments, and be careful with flying debris.