# Drill press chuck with threaded collar



## difalkner (Nov 27, 2011)

I bought this Boice-Crane drill press about 30 years ago and have done very little to maintain it. Recently put a new power cord and plug, rewired from the switch to the motor, even made a depth stop (http://www.woodworkingtalk.com/f13/form-follows-function-drill-press-depth-stop-61801/) but haven't touched the mechanical working end of this machine.

Well, lately I've been doing some fairly detailed work on small pieces with small drill bits and have noticed the slight wobble that has been present for as long as I can remember has gotten worse. It was so bad that a 1/32" bit orbits about a 1/16" radius - pretty bad! It drills true *IF* you hit your mark.

Tonight I decided to pull the chuck off and see just what gives. I've tightened the collar before but it never really was loose. What I thought I'd find is that I need to replace the shaft bearings in the quill (and may still need to do that). What I found is that the Jacobs taper wasn't tight. The collar made it seem tight, though.

Now this may be old hat to some of you, but while I've worked on many drill presses and taken chucks off, they've never been like my own with the collar. So I learned something tonight (never too old, right?). Once I got it off and cleaned up, I used the collar to pull it back up and tightened the fire out of the collar. Still wobbled. I pulled it off again and looked at it closely. Then I realized the Jacobs taper is suppose to be the method for securing the chuck and the collar is just there for insurance.

I ran the collar up, gave myself a little room to 'persuade' the taper to lock, then tightened the collar hard again. Seemed tight when I tapped on it but once I got the collar tight there was still some wobble. Pulled it back off (again!) and this time when I put it back on and gave it a tap (a whack, actually), I only snugged the collar sufficient to keep it from working loose. Now it's tight!

Anyway, there's a video of me seating it and not getting it the first time. I could have done it again or edited it but, oh well. I did go back and tighten the collar a little more after the video. Looks like I bought myself some more time before I pull the machine apart and rebuild it.


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## difalkner (Nov 27, 2011)

*Rebuilt chuck*

I know this really only matters to me, but my drill press has had a slight wobble in the chuck ever since I bought it. Now that I've solved that little puzzle I thought I'd rebuild the chuck. Having never taken one apart I found myself struggling to get the sleeve off, thought maybe I had read the info off the Internet incorrectly. I knew it had to be right, though, because it came from the Internet...

Finally got it apart, cleaned the 40+ years of gunk, lubricated it and put it back together. However, I found it still had that little tight spot that required the chuck key to get past somewhere in the middle of the range when tightening/loosening. So I put it down for the evening yesterday and decided today to take it apart again this evening. Now I can get it apart in minutes and with 1/10 the effort I used the first time.

This time I looked for a burr and found it, removed the burr, lubricated again and put 'er back together. Now it's as smooth as it was likely designed to be. I had my chief videographer do her thing and the video is below. I just find it amazing that I put up with the chuck in that condition all those years.

I also put a couple of .003" brass shims between the threaded adapter and the bottom bearing, put a new roll pin in, and now there's no wobble at all. I don't know what the runout is because there isn't much I can do about it at this point unless I get a better chuck, which I might do even after rebuilding this one.

Anyway, one by one I'm rebuilding all my equipment. I think I'm going to do a quick refresh of my belt/disc sander next. What I'm actually doing is stalling on putting my PM66 back together because I haven't decided what color to paint it. :blink:

Brass shim stock to take up slack








Rebuilt chuck





No wobble


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