I would investigate whether the chuck is made the same as many drill chucks when viewed from the rear. With the jaws below the front surface the outside can be pressed forward using a tube bored to just allow the central part of the rear of the chuck to pass through. It can be done in a large vise if a press is not available.

There have been threads on this forum showing how, or maybe even asking on google may get some help. Ask about “dismantling a drill chuck”. If all fails, then Makita spares shouls have a new one.

I wouldn’t go filing the grooves for the jaws. It’s unlikely to run true if you do that. I’d try soaking the chuck for a few days in some solvent/oil mix or the like. If it doesn’t come good, buy a new chuck. They are not expensive if you don’t feel the need to buy genuine Makita parts.

It sounds like the chuck may actually be slightly deformed rather than just rusty. Since the jaws move freely until the last few millimeters and the mouth looks misshaped, the body of the chuck could be warped (often from a drop or a jammed bit).

I’d avoid filing the mouth—chucks have tight tolerances, and removing material can cause poor grip or runout. A replacement chuck is usually the safer and easier fix. You might also consider contacting the eBay seller since it was listed as “good working order.”

On 10 March 2026 at 19:19 jon man Said:

I’ll order a replacement chuck from the link above, thanks for that.

Please do your own search on the Makita part number as you might find something cheaper overall. I did not see what the postage is on the one above and that can sometimes make a difference.

Get the remains of the old chuck off the spindle first before ordering a replacement. You may find that impossible due to the apparent misuse.

Dennis

Don’t be fooled by brand names. Makita is made in China, probably in the same factory as a generic chuck which will be just as good for a hand-held drill as the so-called OEM item. The cheap machine tool chucks from TEMU etc. are excellent for just a few pounds, despite being dismissed by those who have probably never had one, so I can’t see the cheap hand-drill chucks being any different. But you pays your money and you takes your choice!

Seeing that drive slot, it is unlikely that a generic chuck will be found to fit. As long as the rest of the drill is ok, you might as well get a genuine chuck. A shame you didn’t post photos of both ends. There does not seem to be any threads and it may only be held on the spindle by the centre screw. It would be still worth pressing the outside forward over the front using a bored tube to strip it down and clean it, the jamming might be easier to see and put right.