Changing a drill-chuck adapter

I hope this is an easy question to answer:

I need to change the MT2 adaptor in an all-steel keyless chuck to MT3. How do I remove the chuck from the B16 taper fitting adaptor?
There is a knurled ring around the chuck body with a grub screw. Loosening this screw might allow the ring to turn, but perhaps it needs a real heave? The MT2 adapter has no tang - it has an internal M10 thread, so not much to hang onto. There is no way a drift through the jaws will help, as the inside is steel right across.

I have taken several Jacobs and similar chucks apart, but this one has me beat.

Regards, Tim

Pair of chuck removal wedges will pop the chuck off the adaptor by breaking the grip of the B16 taper. Arc do them and I suspect they are available elsewhere too.

One I prepared earlier

Edited By JasonB on 27/02/2021 18:47:13

Hello Jason

Yes, I thought of that, but with an MT2 adapter the difference in diameter between the two tapers seems hardly man enough. But I will give it a go ... presuming that the ring with the grub screw does not need to be touched?

Cheers, Tim

I had a B16 keyless chuck that kept falling off its taper, a good warm up of the chuck itself with a heat gun expanded it enough to move slightly further up the taper clamping enough never to fall off again, a leather glove helps, it might be worth a try.

Depending on the circumstances, would a MT2 to MT3 sleeve be viable?

I have had to resort to cutting the chuck arbor in two and drilling the bulk of it out of the back of the chuck. This is not as bad as it sounds as the arbor is usually only surface hardened where the tapers have been ground. The arbors are quite easily bent if used on a large radial drill and the chucks they are attached to are swung into a firmly mounted vice. As a result of contractors doing this at work, replacing M4 or M5 to Jacobs taper arbors was on average a twice yearly job.

Martin C

If the Chuck has a through hole as mine has, I have put a short length of 6mm dia rod through the Chuck, gripping it lightly with the Chuck, then strike the end with a hammer. Mine came straight off, but then I had put it on in the first place by inserting it and just tapping the end of the mt on the wooden bench.

If the chuck is a copy of Albrecht etc, the main knurled sleeve is in two parts with a thread between the tightening knurling, and the remainder. As supplied, it is not only invisible, but also very tight. However, if you make up hardwood or aluminium half shells to allow firm damage free gripping, it can be unscrewed.

Dismantling is then straight forward (but don’t loose balls), and there is through access to drive out the arbour.

Success - and relying on the presence of the drawbar thread (so this won't work with a tang);

Screw in the longest bit of M10 you can lay hands on, followed by a heavy steel ring (I used a 50mm flat-belt pulley) which will go over the full length of the taper. Add a nut, and hold the assembly hanging from the nut. Lift the ring and drop it smartly over the taper so it smacks hard against the back of the chuck. Oh, yes, and put something soft like a pair of old TT marshals overalls on the floor below, so the falling chuck and ring don't make too much of a clatter.

Thanks for the comments - next time will be easier using wedges as the new fitting is MT3.

Regards, Tim