View Full Version : Drill Chuck Repair Question

05-13-2010, 01:39 PM
I have an old 5/8" drill chuck that I use for rough work, it's been a good, albeit cheap chuck that has worked hard for me for over 20 years and doesn't owe me a cent.

I was using it the other day to drill out some axle flanges with a 43/64's drill, so needless to say I gave it my customary good tightening on all three jaws to ensure that the dill bit would not slip in the chuck.
Just about the time the chuck was tightened satisfactorily, that sickening feeling of, "I just stripped the teeth off the collar" came over me as I could not tighten or loosen the chuck in either direction.

After disassembling the chuck, I was relieved to find that all was well. As a matter of fact I was kind of surprised to find the teeth on both the split collar and the jaws looked like new! Old Taiwanese chuck, not Chinese.
The problem is that the split collar (C), which normally has the outside collar (D) pressed over it, has spun inside of the outside collar. So while I can still tighten small drill bits that do not require the chuck to be tightened too much, I fear it will spin when trying to tighten larger bits.

The solution that first came to mind was to install two threaded set-screws through the outside collar and slightly into each of the cast split collars.
Anyone else tried this, or have a better solution?

Here's roughly what I'm working with:


05-13-2010, 02:08 PM
How about a shim, .002-.005" or so, stuck in one of the threaded collar gaps?

05-13-2010, 02:26 PM
Buy a new chuck.

05-13-2010, 02:38 PM
You could probably get along fairly well by using Dog Point or Half Dog Point set screws, you could do 1 each side in the middle of the split collar or 2 each side not too close to the ends of each split collar. Make sure the outside collar is pressed on the right amount for the chuck key to mesh with the collar teeth.
Once you put in the set screws you won't be able to adjust the outside collar up or down.

05-13-2010, 02:41 PM
Drill chuck = disposable tooling = buy new chuck.


Alistair Hosie
05-13-2010, 02:48 PM
I am afraid I have to agree with the others. It seems to me you've had a good life out of the chuck maybe time to contemplate getting a new one.If they were tremendously expensive I would say fight on, but great chucks can be bought cheaply enough on ebay etc. I have quite a few.Alistair

05-13-2010, 11:05 PM
Well yes I could just stick another chuck on the drill press, I have about four or five good chucks to choose from. But that's not the reason I have a large investment in a shop and tools. Let's face it any yutz can buy new stuff whenever something is worn or in need of repair. I prefer to repair rather than discard, at least when viable.

I wasn't prepared to spend two or three hours to fix this chuck either, it's not worth it. However it has been a good chuck and still is except that the interference fit between the outside collar and the inside split collar is not quite as tight as it should be.

Strokersix: I wish I could have done it the way you suggested but the splits in the threaded collar are fractured splits in cast, so it has to go back together at the split so that the fracture goes together precisely, much like a fractured con-rod.

Toolguy: Your method is the one I first thought of too, and I'm sure it will work. All I have to do is drill and tap four small holes, won't take long either.

What I ended up doing was even quicker. I put a light knurl on the inside of the outside sleeve. The outside sleeve goes on much tighter now then when it did before, and I can tighten a 5/8" drill as tight as I want, so it's fixed, and with a little luck good for a few more years.

05-14-2010, 01:37 AM


05-14-2010, 08:12 AM

ditto on loctite

05-14-2010, 08:25 AM
I also like the Loctite idea. And as for tossing the chuck out, it all depends on what the users goal is.

If I were back at the big assembly plant, I would get a new chuck out of my supply, put it on the machine and turn production back on. New chuck = a higher probability of no failure. The old chuck would go into a "round tuit" pile. And if we had some spare time to get a round to it, we would find a rebuild kit and fix the chuck as a backup. If the pile got too big, I might sell it to a machinist for scrap price.

A second scenario - In the small shop, I would do what I could to save a dime and make the old chuck work again knowing that I might need to replace it soon. Shims, Loctite, set screws what ever. My time is worth some amount of money but that can vary as I see fit. It might be worth it to me to save the chuck.

In the end, it all depends on what the users goal is.

Although I do find it funny that there is so much talk about saving old clapped out, rusty, cant find a part for this machine, I don't think that it will ever run again, I bet I can scrape that thing back in, iron that I am surprised to see the "toss it out" comments. But back to my original statement, it all depends on what the users goal is.