V2.18 - Drill Presses and their chucks: part 2

Last week we talked about putting your drill chuck on your Drill Press. I ran out of room to fully explore the subject, so here we are again.

We were at the point of what steps to take when the chuck won’t stay on the taper… it keeps falling off when you try to use it, or maybe it won’t even stay on when you try to put it on. So, we said, the first thing to do is to check and clean VERY THOUROUGHLY the taper on the DP and the chuck’s taper.

NOTE: while you are checking/cleaning those tapers, this is a good time to inspect the surface of the tapers closely. The tapers need to be smooth and free from any galling. ‘Galling’ is a machinists term that refers to the tendency of metals, when scrubbing together under force, to grind and scar each other. If your chuck has been loose on the spindle nose (unknown to you) for a while, the two parts may have galled their surfaces. IF they have, it is usually useless to try to get them to properly seat again. (The prescription is to replace both parts and start fresh.)

Ok, let’s say that you’ve checked for galling and found both the chuck and the spindle nose taper to be smooth and in good shape. Now, you’ve cleaned them again and they are absolutely oil-free and dry as a bone. Take the chuck and ram it sharply onto the spindle nose.
Now, it’s time for the 2x4 and small sledge hammer again. Swing the table out of the way so that you can get a pretty decent swing with your sledge. Retract the chuck jaws to prevent them from getting bent and put your 2x4 under the chuck. Hold the 2x4 with your ‘weak’ hand and use your dominant hand to swing that sledge upward and SMACK the 2x4 (which is against the chuck) very hard.

As I said last week, Tapers seat best with a shock to them. A good 3lb sledge and a 2x4 block will allow you to deliver that shock to the chuck without risking damage to your chuck or Drill Press.

If you continue to have your chuck fall off, there may be a misfit between the two parts, or you may be asking the Drill Press to do something it was not designed to do (like milling, or using an out of balance item in the chuck) and the design of the chuck/spindle taper was not intended to account for that.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you.