Drilling problem

[Gary]

Having found this site so useful in the past I thought someone may be able to help with my latest challenge.

I have to drill a couple of 10mm dia holes in a brass chapter ring for a clock. The brass sheet is about 0.5mm thick.

Any suggestions for getting neat clean holes using commonly-used tools? I did a trial one today and although I thought I had the ring securely clamped to a wooden board it moved when the drill tip broke through and jammed on the bit. Someone suggested making a "sandwich" of two layers of ply with the brass between and then drilling straight through?

All suggestions welcome!

Regards

Gary

[Andy]

Another tip when drilling brass, is to remove the outermost tips or the drills cutting edges using a bench grinder. The reason is it stops the drill 'grabbing' as it tends to do with brass.

[Gary]

Sorry for the delay in getting back to the forum.

Thanks to you both for your responses, I managed the job by using the sandwich method and took the advice to clamp as close as possible to the hole.
I'm afraid I wasn't brave enough to start grinding drills but if I get a similar task I will have a go.
Thanks again