Drill geometry for 0.020" dia., 0.250" long hole in brass.

[beavers]

We have to drill a 0.020" dia., 0.250" long hole in a 0.060" outside diameter brass rod. The final product overall length is 1". Everything is done on a high production screw machine, from 10-feet long rods.
What is the best drill geometry, drill type for this application? Also, speeds and feeds to use with this drill?
Main concerns: drill life, chip removal/breaking, hole concentricity with the outside diameter (+/- 0.001&quot.
We've had some success with slow-helix drills, but the results are very different from manufacturer to manufacturer. They all tend to be pulled in (and then break), because of the soft material being drilled.
Is there a reliable drill supplier (with applications engineers) in North America?

 

guhring makes a fantastic line of production drills for all materials. contact a supplier such as msc, kbc tools, or j&l industrial supplies.

 

[sbc]

You have several problems here. The cutting speed for
ordinary brass is 160-180 feet per minute. A .020 hole
requires more rpm than you can get with a screw mach.
The feed rate should be about .0004 to .0008 I.P.R.
The reason that the drill is being pulled in is too
much clearance angle. Concentricity will be affected
by all of that stock hanging out of the back of the
spindle. I wouldn't want to be around a 10'x.060 pc
of wire at full speed. Even if you capture it inside
a pc of tubing it will twist & rattle. I would recomend
that you rough cut the o.a.l., then finish face, spot
& drill in a small high speed machine like a Hardinge.
I realize this will increase the time factor, but it
seemes necessary. If implemented you should find that
you can run more parts between inspections.
Hope this helps. jw