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I'm a novice woodworker doing some basic projects. I recently acquired a drill press and a set of hole saws with hexagonal shanks.

The hole saws have a disturbing tendency to come loose from the drill press as I'm using them. I think the root of my problem is that my drill press has a 4-jaw chuck and so a secure grip on the hex shanks is not possible.

Is there a recommended technique for adapting hex shanks to a 4-jaw chuck? Some device I should buy?

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  • A model number for your drill press would better help us help you.
    – Eli Iser
    Oct 3 at 23:11
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    There are some workarounds to provide grip in this sort of situation (e.g. using some sort of conformable wrapping, like copper), but I don't believe the grip will ever be as secure as it could be with a 3-jaw. When three jaws are used to grip anything with a hex shank the shoulders are physical barriers to movement, pretty much eliminating the possibility of slippage during high-resistance usage. Besides, you're much better off using a 3-jaw chuck anyway (in a drill press, it's different in a lathe) because they're self-centring.
    – Graphus
    Oct 4 at 5:43
  • "When three jaws are used to grip anything with a hex shank the shoulders are physical barriers to movement, pretty much eliminating the possibility of slippage" may be the case, @Graphus, but I have the hardest time getting those stupid hex shanks to line up properly in my 3-jaw hand drill chucks. I really despise them! I frequently have the bit (often a large hole saw) slip because I just can't get the jaws to line up with the flats, especially on larger bits where the jaws are in the chuck not sticking out. If you've got tips, I'm all ears!
    – FreeMan
    Oct 4 at 16:29
  • @FreeMan — zip the chuck almost closed with the hex thingy in it, back it off a tiny bit, wiggle the hex thingy, then zip the chuck fully closed.
    – Aloysius Defenestrate
    Oct 5 at 0:35
  • @FreeMan, not sure what to say cos I don't have any difficulty really. Sure it doesn't always happen 'automatically', but then I eyeball it (and I have excellent close-up vision over the rim of my specs) so I can see what's going on. Normal method, I guess, is to open slowly until the hex can just go in and then it pretty much is automatically aligned.
    – Graphus
    Oct 5 at 6:13

2 Answers 2

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Drill presses usually have a standardized chuck connector, such as Morse Taper (MT) or Jacobs Taper (JT). These are followed by a number to denote the size (MT2, JT3, etc.). You can take your existing chuck out of the drill press (typically using a small wedge driven into a slot above the chuck), verify the correct taper and purchase a replacement chuck with 3 jaws.

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As mentioned, the best option is to replace the chuck. Having different types of chuck is useful regardless.

If that is undesirable for some reason, you could try getting a hex-drive extension. Those generally have round exteriors that will secure in your four-jaw chuck just fine. You may have to cut the hex shaft off of it to fit depending on the extension and the size of your chuck. This will be a little looser than using the proper chuck. Also you probably want to get one of the extensions that has a locking mechanism and not just a magnet, otherwise retracting the hole saw might get a little awkward.

If your hex shafts are not one of the standard sizes, then a socket will often work, either by itself or with a socket extension. But now you're getting really wobbly... Might be best to glue the joints together.

Be really careful with any cobbled-together solutions as a small amount of instability can lead to rapid, unplanned disassembly when rotating at the high speeds generally used for woodworking. Hole-saws shouldn't be too big an issue since they're normally used at lower RPM, but be sure to keep your fingers well back and your face out of the danger plane regardless.

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  • "rapid, unplanned disassembly" Hehehe.
    – Graphus
    Oct 5 at 6:09

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