On Oct 25, 4:24 am, "Nightjar \"cpb\"@" "insertmysurnamehere wrote:
On 24/10/2010 12:50, 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.
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!

If you want to do it by machine, rather than by hand, the correct
equipment is a spindle polishing machine with a calico mop and brass
polishing compound. A flap wheel is far too aggressive for polishing brass.

The bells have been cast in sand, so I need to take a lot of metal off
before using the spindle polishing machine. They are plenty thick
enough. I could take 1mm off if necessary. That will alter the pitch
for sure!