Hey, I designed this a while ago, and it has a few increments most people won't use, but it has the standard ones.

Holes are in mm, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 4, 4.2, 4.5, 5, 5.1, 5.2, 5.5, 6, 6.8, 8, 8.2, 8.5.

Print top and base, I've used M4x30mm standoffs to seperate and keep the holder square-ish.

Ream the holes, and the tapered holes in the base so that the drill bits fit loosely.