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I have an old General International drill press (model 17-125M1 — so old that the GI website does not even show any results when I use their "Search" facility).

It works for the most part well, except that occasionally, the head (the chuck) just falls. Usually not dangerous, but still an annoyance; plus, some times it ruins the wood piece.

When it falls, I simply push it up and slightly twist it counterclockwise, and it seems to just snap in place. But it does not solve the problem (in that it may continue to work at that moment, but at some point the problem will repeat). For example, trying to use a countersink bit on a piece of plywood seems to be hopeless (the chuck falls every single time).

How would I go about fixing this for good? (I would like to try to fix it myself before getting it repaired, since I estimate the cost of getting it repaired may be too high)

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    Good to hear this was indeed a Morse taper chuck. Note there are some reasons these can become loose, and one of the classic ones is just the least amount of schmutz inside the bore or on the chuck taper, a problem that can become exacerbated after the first time the chuck drops out! You want both spotlessly clean. If you still find it has a tendency to work loose there's the chance that the taper has worn, this is fairly rare from what I understand but you note the drill is old so it is a slight possibility. – Graphus Dec 6 '20 at 0:16
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    Yes the jaws are the three metal pieces that 'grab' the bit. And "fully retracted" just means they no longer project from the chuck. They don't have to be retracted as far as they can go, sorry that's a classic example of ambiguous meaning in English :-) – Graphus Dec 7 '20 at 8:40
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Does the chuck have a tapered shaft on its back end? That is called a Morse taper, developed for quick-change operations back in the day. The proper way to re-install it is to slide it into place, retract the 3 jaws into the chuck body, then use a hammer and a wood block to bang it upward sharply. The slight taper (about 2 degrees) helps it lock in. When they wanted to remove or change it, a light tap downward onto the chuck would pop it free.

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  • Dead on! It is indeed a Morse taper chuck — I just re-inserted it and hammered it up. I'll see how it goes during the next few uses. – Cal-linux Dec 5 '20 at 18:46
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    @Cal-linux, do note when tapping or pressing a Morse taper chuck home the jaws should be fully retracted beforehand. Also see Chris Marshall's alternate technique here. – Graphus Dec 6 '20 at 0:22
  • @Graphus ‒ not being a native English speaker, I often have trouble with terminology. I can't find any labelled diagram showing the parts of a chuck, in particular the "jaws". I think I know what those refer to (and yes, I retracted them before hammering, even if I used a piece of wood, and a mallet (rubber) instead of a hammer). To confirm, seeing this image, upload.wikimedia.org/wikipedia/commons/thumb/e/e1/…, the jaws would be the bottom-most part, right? the ones that hold or "grab" the bit, correct? – Cal-linux Dec 6 '20 at 14:34
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    As soon as the 3 jaws are hidden within the body of the chuck, you are safe with the wood block, etc. Sorry I didn't mention that in my answer. – John Canon Dec 6 '20 at 19:47
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    @JohnCanon, you can edit your Answer at any time to add info such as this, to correct something, clarify meaning or add details you think of later or that arise from further research. – Graphus Dec 7 '20 at 8:42

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