Hello,
Drilling Brass, Bronze, Copper or any other non-ferrous metal, with a standard drill bit, is not easy!.
The cutting edge of the drill spirals into the soft metal and can break the drill, or pull the drill out of the chuck.
The cutting edge has to be modified from the standard edge, but, once modified, must only be used to drill non-ferrous metals, used on Steel will destroy the drill bit.
Hold the largest drill bit you have, by the "chuck" end and look at the cutting edge, it sweeps down to a sharp end, this edge has to be made flat.
This flat must be vertical to the body of the drill, so instead of a sharp edge there is a small vertical flat where the sharp edge was before.
Do not "blunt" the drill, the flat should be in line with the body of the drill, a line drawn up across the flat should reach the Chuck.
This flat edge will enable the drill to produce "chippings" rather than the normal spiral cuttings, it will stop the drill from grabbing into the soft metal.
A small grindstone in a Dremel or similar tool, will quickly grind the very small flat required
The drill can now be run at the normal speed for the diameter of the drill and will give a much better finish to the hole produced.
A drill bit modified as above can drill Plastics, Lead, Aluminium, all the things that were "hard" to drill previously !!.
BUT !, if the modified drill bits are used on Steel, they MUST be resharpened first.
This is very difficult to describe and even harder to draw!!, but oh so easy to do !!.
Lathe tools also benefit from this method of making a small flat on the cutting edge, but they too can then only be used on soft metals, until they are resharpened.
John,