[Boatanchors] Probably OT: Drill press runout question

[David Knepper]

Try shrink tubing



David Knepper - W3CRA/W3ST
Collins Radio Association
www.collinsra.com
Join the CRA today
-----Original Message----- 
From: hwhall at compuserve.com
Sent: Monday, April 28, 2014 10:46 PM
To: milsurplus at mailman.qth.net ; boatanchors at mailman.qth.net
Subject: [Boatanchors] Probably OT: Drill press runout question

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
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