by Alexander M.
We have all read Blame’s post about cleaning out the dust and old grease, to reduce wear and improve concentricity. But what about drill chucks, they certainly can benefit from disassembly and cleaning, however the lack of screws make it seem impossible to disassemble. It turns out that by pressing out the sleeve, the whole thing unravels. Here I have a Jacob’s ball bearing super chuck that I was given in damaged state. When turning the sleeve there was a gritty feel and there was a broken stub of an arbor stuck in the tapered end.
What you need first is two sleeves to allow for the chuck to separate while force is being exerted. These can be made from either steel tube segments or from boring metal round bar. The larger of the two is used around the sleeve of the chuck in both disassembly and assembly. The smaller one is to add spacing around the jaws when pressing. You must not press out the sleeve with jaws fully retracted because they flare out in the back portion and will prevent removal. You also must not exert force on the jaws, doing so risks breaking the threads on the inner nut.
For the pressing, an arbor press is most ideal however a Kurt vice is a good substitute. Before pressing the chuck apart, mark each of the 3 jaws so that you will know the order in which they need to be re-assembled.
Editor’s Note: I’ve found that it’s easiest to mark parts with dots or punch marks than with actual numbers. So instead of trying to draw the tiny numbers 1, 2, and 3 on each of the three jaws, put •, ••, and ••• tiny dots from a permanent marker on the jaws instead. Don’t forget to also mark the corresponding slots in the chuck housing with matching dots. – Tyler
These are all the pieces that can be found in a chuck.
This particular chuck had a section of an arbor that had sheared off in the tapered section, this was remedied by drilling out the section of metal dividing the two ends and driving out the stub with a screw as a drive pin.
Using a solvent such as paint thinner or alcohol, the grease can be easily removed. Make sure to allow time for the solvent to evaporate so that it doesn’t dissolve the lubrication.
Before re-lubricating I recommend doing a dry run assembly starting with the three jaws and the raceway, then the split nut.
When installing the split nut can be tricky getting the jaws to line up. Start with aligning the three jaws by making them flush with the body, then rotate the two split nut pieces until they fall into place.
If the jaws are set correctly they should come together at an even point. If they don’t then you only need to switch two of them. As I mentioned earlier, to save yourself some confusion it will be worth marking the jaws and their original location before disassembly.
Following lubrication the chuck is ready to be pressed back together.
This refurbishment is now complete!
If you have any questions please leave a comment via the forum discussion link below. Thanks!