[Boatanchors] Probably OT: Drill press runout question

[hwhall at compuserve.com]

I need to drill some very small circuit board holes for a project, #64 drill size (.036 inch). My drill press chuck wouldn't grab a bit that small, so I got a mini chuck to fit into the press. The mini chuck shank is 1/4 inch. When I installed the mini chuck, the drill bit wandered in a circle, like a case of runout. Not like a bent bit, the whole length of the bit was moving around. But when I put a 1/16 inch bit into the drill press, there isn't any runout anymore. 

Thinking the mini chuck to be faulty, I looked around the workbench some more and found a hand drill that would grab the #64, and it ran true when I turned it, so I removed it and inserted it into the drill press. It had a 5/16 inch shank. This combination also showed wobble. But the drill press still will turn a small diameter drill bit without noticeable wobble.

It's as if the wobble turns up only when the drill press chuck is made to hold a larger diameter, and goes away with the smallest diameters. Does that make any sense or suggest something that I should inspect or adjust?

Thanks!

Wayne
WB4OGM