Matty F wrote:
A number of bells have been cast in brass. The castings are somewhat
rough, and the outside needs polishing.
I don't see how to do this on a lathe. The castings are not perfectly
round and would need too much metal taken off.

well cast them again properly!

There is a hole in the middle, andI I propose putting a bolt through
and spiinnng the bells slowly in a drill press while using a flappy
wheel on an angle grinder to polish them.
Unless anyone has a better idea!

Do it right second time. If you want a proper tone, they need to be
trued up.