Thread: Removing seized mt2 chuck from spindle

Originally Posted by ml018

Attachment 376532 The problem is difficult to clamp the spindle down so that the force when hitting engages the entire face of the spindle bottom. I am able to put it in a large vice but the hardened spindle face is thinner and all the force is directed against that thin portion (like on the diagram) against hardened vice jaws. This face is what sits against the needle roller bearing and any slight bends to that surface could have a negative impact on the accuracy of the spindle.

I used propane but the spindle took too long to heat up so I might have to try MAPP gas. I don't want to damage the spindle as it will be almost impossible to find another one and having one made would probably exceed the cost of buying a new or pre-owned milling machine.

A new 2MT ER25 collet chuck is maybe $40, I bought one the other week. Cut the thing off, fully support the spindle then smack the drawbar cushioned with brass etc as described already with a BFH. If it doesn't move, drill out some of the centre of the 2MT stub and do it again. Sooner or later it WILL move.

PDW

I wouldn't hold it in a vice, it will shrink the spindle and defeat the purpose. The spindle has a step and use that instead.

I can't imaging MAPP would damage the spindle, it either gets hot or it doesn't.

Originally Posted by .RC.

Why put it in a vice?

Since you have it out my preferred option would be turn it upside down grab the spindle and hit the drawbar against something very solid.

I only put it against the vice jaws right before hitting it. As for hitting it upside down against something hard, proved as useful as all other attempts.

Originally Posted by PDW

A new 2MT ER25 collet chuck is maybe $40, I bought one the other week. Cut the thing off, fully support the spindle then smack the drawbar cushioned with brass etc as described already with a BFH. If it doesn't move, drill out some of the centre of the 2MT stub and do it again. Sooner or later it WILL move.

PDW

I don't think it's worth the hassle. It has a schaublin collet chuck (ER20) which spins very true. The Chinese chucks are usually a hit or miss, I might just try to find an entire spindle and replace it (I'm not in a rush).

Originally Posted by Pete F

I wouldn't hold it in a vice, it will shrink the spindle and defeat the purpose. The spindle has a step and use that instead.

I can't imaging MAPP would damage the spindle, it either gets hot or it doesn't.

I am yet to try MAPP gas. How should I hold the spindle so it is safe to do so (thick leather gloves might not be enough?)? I previously put the spindle into the lathe and turned at a slow speed apply the heat more uniformly but that probably dissipates the heat too quickly.

Hi Mlo18,

The trick is to apply continuous pressure in a direction that will remove the chuck and then apply as much heat as you can as quickly as you can to the area where the chuck is held. The idea is to cause the shaft to expand before the chuck shaft has started to. Some one mentioned freeze spray, that would be a good idea as well. But it would need to be used in conjunction with the above. Also if the spindle can be held solidly at the same time, you could also pre-load the spindle bore so that you can give it a thump from the back as well.

Though I'm starting to think that if its that solid, machining it out could be the last resort. If non of that works then, yes it could be a new spindle time.

A new spindle! Holy cow, I don't think so. This is a very common thing to happen, and unless it's been stored at the bottom of the Dead Sea for the past 30 years, the tapers will unlock when sufficient force is applied. How much is "sufficient", that's the big question, but this is only an MT2 taper so it's not going to be crazy amounts.

When mentioning how to hold it etc I do think you're over thinking some of this, just make up some form of register so the spindle can stand vertically and be registered on the bearing step. If you have a lathe you can bore and weld a perfect jig for this. Heat the spindle as quickly as you can. If you have a MAPP torch and a propane torch, put both of them just up from the end of the spindle and heat it as fast as possible. While temperature helps, it's the difference in temperature that's more important. I wouldn't waste my money on freeze spray as I've found it just doesn't absorb enough heat. I'd be more inclined to drop the whole lot in a chest freezer before you started working on it. I've done that when shrinking components on and it works well, one goes in the freezer, the other goes in the oven and away you go. Whatever you do you need to work fast.

Stand the spindle in your jig and smack the crap out of the loosened drawbar. If it doesn't release use a bigger hammer. I have a fitting that goes on the end of a jackhammer for driving star pickets and I might try that, but probably wouldn't bother and would just use a club hammer first time, if that didn't release it then use a sledge hammer. Don't hit your mate who's holding the spindle

What you don't want to do is muck about with this. If you half- your hits and tap away at it you will just peen over your drawbar nut and make a mess of the whole thing. One BIG hit will release the taper, pretty much guaranteed.

This is the whole reason I really hate slow tapers as they either spin or lock real tight and in a milling machine invariably take quite a hit to release them. Not good for precision bearings in my opinion.