I agree with Tim: It’s all a plot by DeBeers.
My suggestion would be to go with short drill bits. Go to an
industrial supplier, and get what are called ‘screw machine’ length
bits. They’re shorter, so they’ll flex (and wander) less.
If you happen to know a tool & cutter grinder, have him cut them
down, and resharpen them as 120 degree split-point drills, with
about 4-6mm of flute left. Those won’t wander at all, but it
requires knowing someone who makes his living re-grinding tools.
(Just for the record, when Knew Concepts started out, the guy in the
next bay over was a very good cutter grinder. He saved our tails
so many times, both in sharpening tools while I waited, and in
making custom tools that let us do two or three things at once. A
good cutter guy is not to be taken for granted, but rather to be
You are doing the drilling in a drill press, right?