Jacobs morse taper chuck.

Is there a correct and easy method of removing a jacobs chuck from an arbour? Or once its pressed on is that it fixed.

If so can anyone enlighten me please.

Jon

Two wedges and a big hammer ?

Chuck removal wedges. Come in different sizes to match the JT taper:-

Either use hammer or squeeze in the vice. Used as a pair, fit between the back of the chuck and the collar on the arbor.

John

Edited By Journeyman on 18/06/2020 13:10:41

I have resorted to cutting off the bulk of the arbor, leaving enough to grip (a split collar can be made for this), and drilling out the core to reduce the pressure on the Jacobs taper The arbor is mainly soft so no problems drilling them. Recommendations for a new one is do not fit it with a press.

Also check if there is a through hole in the chuck. You may be able to drive it out with a pin punch but I think the hole is very small and is to allow air to pass for assembly/disassembly.

Martin C

Most of mine are drilled through and tapped for a jack off screw. Obviously, you have to have done this in advance!

+1 for folding wedges.

I managed to get one apart recently, having tried the wedges and failed, by drilling a hole down the centre of the arbour, into the void at the back of the chuck. I filled the hole with oil, then pushed a short piece of rod as a piston into the drilled hole. I was surprised how hard I found myself hitting the end of the piston to get the hydraulic shock enough to pop the taper.

And of course I was lucky it was a homemade arbour and had been left soft so I could drill down the centre of it.

Regards Simon

Drill chucks can be either held just on the taper, or sometimes held with an additional screw from inside the chuck. I just open up the jaws and place a bar inside and strike it to pop off the taper. In addition chucks can be screwed on like on portable drills.

Wedges will remove the chuck complete with arbor from the spindle. They will not separate the chuck from the arbor under normal circumstances unless the arbor is drawbar threaded. JT to MT arbors are usually tanged.

Martin C

Typical JT-MT arbor

Edited By Martin Connelly on 18/06/2020 14:24:23

By far the easiest way is to open up the chuck and select a drill which will pass between the jaws without touching them and drill into the void in front of the arbor. Then use the biggest punch that will go down the hole and knock the arbor off. I did one the other day, and still haven't found the arbor amongst the junk in my garage. The wedges are mostly a waste of time and money. Wedges would have to be used if the chuck is keyless, you cannot drill them without destroying them. 

Electric drills which have reverse have a chuck which is screwed on. The screw down inside the chuck has a left hand thread to stop the chuck unscrewing when in reverse. The easy way to remove one of these after removing the screw is to put a large allen (hex) key in the chuck, tighten up and strike the end of the key with a mallet. Put the drill in low gear if it has one.

Edited By old mart on 18/06/2020 14:34:58

Chuck wedges are designed to go between the chuck body and the ridge/collar on the arbor, they are not designed to remove the arbor from the spindle.

In fact the splitting of chuck and arbor is probably better carried out away from the drill or mill.

There is also a circular wedge tool for the same job:-

John

Edit: Add image

Edited By Journeyman on 18/06/2020 15:22:21

That "circular wedge tool" is part of a bearing puller, and the tapered edge is designed to pull a ball race off something like a motorcycle crankweb.

Yes, indeed it is but can apparently be used for the job in hand. Can't say I have ever used one though!

John

I read many years from a chuck manufacturer to drill a hole through the back of the chuck and knock out the taper with a punch. Only needed to do it once but was surprisingly easy once you know.

Some other makes of chuck already have a hole, the one I did the other day had a hole the size of the end of the arbor, why Jacobs had to be different, I have no idea. We inherited an unused British made Jacobs chuck of 1/4" capacity on a MT1 arbor. We do have 1-2 adaptors, but I drilled it and fitted it to a MT2 arbor so it would fit the lathe directly, or the mills via a tang type R8 adaptor. It runs 0.0015" tir which is plenty good enough for us.

Hello,

Thank you for all your responses, I have a Bearing pulley exactly like the one shown, i will give it a try first. failing that ill go down the drill and knock out route.

The reason that i wanted to get the taper out is i believe the taper is bent and it doesnt run true when holding drill bits. I'll be mounting it onto a new arbour. If that doesnt work then i'll go down the route of buying a new one.

Jon

Before you take drastic action, can you mount the arbour and chuck on thedrill/ lathe spindle then check the chuck body with a DTI, ie the part in which the key-holes are drilled? If that shows run out, then it's good evidence that the arbour is in fact bent. If not then the chuck jaws could be where problem is.

We had a big Asquith radial arm drill (MT5) where I worked and it regularly had a chuck swung into a vice or other solid lump. The arbors bent very easily when abused like this which was good as they are normally easily replaced. The point is, always assume the arbor is bent as a first action. This is also why I have experience of removing many of them.

Martin C

Auto correct corrected! 

Edited By Martin Connelly on 19/06/2020 10:18:12

I have used the wedges to remove a chuck from my bench drill when changing from keyed to keyless chuck, they are awkward to get started but not difficult, I used a large 'G' clamp to push them together, they work efficiently, having checked on ArcEuro it seems that they no longer supply them, mores the pity as they were cheap enough, a couple of quid iirc, usual disclaimer applies.

George.

I have destroyed the morse taper on an arbor trying to remove it with bought wedges, I have also destroyed the wedges trying to do it. I made some wedges as well and destroyed them. I did manage to get one off with the open end of a combination wrench hammered in to the groove. I have had to drill a few out to remove them, it always works doing it that way.

Martin C