"Bill Chernoff" wrote in message
news:%q3Ac.732915$Pk3.3341@pd7tw1no...
I am drilling 13/64 holes 2 inches deep in 6061. The bottom of the hole
wanders as as much as 0.020-0.030 off center. What is the best
straightness
I can hope for on a hole that size, that deep?

Any drill sharpening, etc, hints?

As others have said, center or spot drill first.

No one suggested predrilling with a smaller diameter drill. Something like a
1/16" drill would be good. The web in larger drills (especially those which
are dull or badly sharpened) tends to push the drill around.

Don't cram the drill into the material. Push firmly but let the machine do
the drilling. Peck every couple of seconds as well. Developing a good feel
for how a drill bit should be drilling is important on manual drill presses.
This feel can tell you when the machine is about to toss your piece,
break/melt your drill, or drill a straight and correctly sized hole.

Slow down your RPM if you feel like you have to push hard to eliminate
chatter. The standard (4xCS)/Ø formula will yield an RPM of about 6,000.
This is certainly too fast. I'd go about 1000. It won't hurt the drill and
(if you don't have hundreds of holes to do) time should be ok too.

HTH.

Regards,

Robin