It could be worth doing a blue check to establish the tapers are not damaged and match each other. They should not need hammering as the taper is designed to self hold and should not need much more than a good tap to mate firmly. A job that causes vibration or side loads can loosen a taper. Is this a machine with a chuck taper as the spindle nose or a chuck mounted on an arbor to fit a morse taper spindle? Is the taper that comes loose the one in the body of the chuck or the arbor to spindle taper?

Mike

Regrettably hammering a drill chuck onto its taper will almost certainly wreck the tapers.

Right way to do the job is to sit the chuck on the taper adapter wit the tang side down and bang the tang end down hard on a solid, non deforming, surface a couple or three times. The jolt and vibration should set the taper so tight that its immobile without wedges or an extractor. If it doesn't one or both tapers is bad enough that, short of welding, the thing will never hold.

Are you sure the tapers actually match.

Some of the metric B series are so close to the JT series that its nigh on impossible to tell the difference without careful measurement. Except they won't hold. B16 I believe is the example I ran into long enough ago to have forgotten the details.

If the chuck is an inexpensive one, most likely of a certain vintage, it may not have a correct to spec taper in the body. The aforementioned B16(?) issue was with a chuck that could not be re-attached to the arbor it came with. Investigation showed the chuck body taper to be pretty much midway between the B series and the closest Jacobs. The arbor was to spec and had clearly been pressed on with very heavy force. I ended up re-cutting the taper in the chuck body to correct specification and cleaning up the scrapes on the arbor. Chuck body was quite soft.

Clive

Do you remember if you were doing anything unusual or a non drilling activity the first time it came loose? The tapers may have collected some damage when it first came loose and no longer locks like it should, a very close examination and cleaning and then check with engineers blue to see if they still have a good match.

Mike

So, is it the Morse taper going up into the quill that is coming loose? Or is it the short taper that holds the chuck on to the end of the arbor that is coming loose?

The latter can be fixed with Loctite. The former is probably some burring on either the male or female taper that needs removed.

Aha! Thank you. That makes much more sense now.

In which case, Loctite is probably the most expedient solution. (No pun intended ) I won't specify the grade. One of their high-strength retaining compounds. But not the high-temp one if you ever want to get it off by using heat.

In which case the problem may be sloppy bearings or the chuck has begun holding a drill off centre due to wear. A short taper like a J33 can't take any horizontal wobble at all.

But in this case it's spindle direct to chuck so that may give dismantling problems later.

Hi Howard,

If they are properly lapped together there will not be any space for the sealant, if the parts are assembled correctly.

.

Sorry to disappoint you, but anything rougher than a ‘black-polish’ should have plenty of surface texture for the usual anaerobic retainers to do their job.

MichaelG.

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Recomended reading: https://5.imimg.com/data5/AE/AX/JM/SELLER-2044578/loctite-retaining-compound-638.pdf

Edited By Michael Gilligan on 19/05/2022 17:09:53