Firstly, you will lose a large amount of your impulse if striking on a loose thread.

One suggestion might be to do some side milling without the drawbar being tight. It is there to retain the tool in position, after all. Beware that running with the tool loose in the taper could cause damage, so care is needed if trying this.

One cause of over-tight morse tapers is a mismatch of temperature when fitting. A cold taper tightened into a warm taper can result in an extremely tight 'shrink-fitted' tool.

A heavier mallet is another alternative – probably OK as long as you don't use a steel hammer! Never a steel hammer, ever, for this job.

Fortune favours the brave! As it's jammed, you're going to have to hit it harder. Position a bit of aluminium plate (2 or 3mm thick) on top of the drawbar to cushion the blow and then hit the drawbar with an ordinary steel hammer. Do it somewhat more energetically than has been tried before.

John's tubing suggestion sounds like a good idea but I suspect the worry about drawbars and bearings is greatly overstated. If you search the literature you find loads of gents fretting about the possibility that they might damage a bearing by hitting the drawbar and none who've actually broken one!

The key is in the 'sharp whack' – breaking the taper's grip is about momentum, not pounding. Ineffectively banging on the drawbar without breaking the taper is likely to hurt the bearings – eventually. My theory is that, normally, most of the energy that might damage a bearing transfers into the ejected tool, but only if the tool comes out. In other words, don't pussy-foot.

Dave

I normally tap the collet/tool sideways to release it rather than banging on the drawbar. Remember the theory that you shouldn't mill without using a collet drawbar as the sideways vibration loosens the driving taper? It makes sense to reproduce those forces.

Andrew

If you are going to use a "wedge" technique it would be better to use two to form a pair of folding wedges thus eliminating any tendency to bend anything sideways IYKWIM.

Yes it will be a blind hole. Sorry I read your original post as a collet stuck in the taper as opposed to a collet chuck jammed.

As mentioned elsewhere, try milling something with the drawbar loose ( leaving it in situ, to avoid damage if it does release.)

There are pairs of wedges available for separating chucks from quills or arbors, which aught to do the job.
I'm sure a bit of work on the mill will make a pair for you. On the bright side, you might even release the chuck whilst you're making them.

Get some pipe freezing spray or something like 'Shock Unlock' and use a tube to direct a good dose into the drawbar hole of the collet. Leave for a minute or two, repeat, then give a sharp tap with brass drift.

Neil

When I had an open ended MT sleeve jam in the Mill/Drill, there quill was too narrow to admit a drift the contact the back of the sleeve.

I made up a sort of top hat bush, with a thick rim (3mm) the outer edge was tapered, and the bore was tapered (using a centre drill ) and split, four or six times with a hacksaw. The OD of the rim, before splitting was greater than the bore of the sleeve. A tapped plug, with an outer taper to match the top hat taper, was Loctited to a piece of studding, The top hat was fed onto the studding, closely followed by a nut.

A Cup, with recess larger that the outer end of the MT sleeve was made up an fitted over the studding. The studding and split top hat was tapped (pushed ) through the MT sleeve so that the split end popped out of the inner end. The cup was placed over the studding, followed by a plain washer and a nut. Tightening the nut pulled the tapered p[lug into the split top hat and expanded it so that it overlapped the end of the sleeve. Further tightening pulled the sleeve free from the quill. If plain tension does not shift the collet, a slight tap on the end will often jolt things free.

Crude, but it works (repeatedly! )

If the above is not clear, PM me and I'll take a picture of the gadget, and E mail it to you

Howard The one with FAT fingers

Edited By Howard Lewis on 06/03/2019 10:47:55

Edited By Howard Lewis on 06/03/2019 10:48:36

Done this a few times over the years its quite easy to fetch out as mentioned above.

Just put a packer in about 12 will do and knock the drawbar down with nut on.

Almost certainly drawbar had it next time make a better one with hex solid one piece on the top. Will have to measure as necessary, done it at least 20 times in 15 yrs on a Lux and RF25.
Tip the all thread is weak and will soon strip the thread, either make it one piece from decent hardened steel or cut a 12.9 bolt and weld to a shaft.

Best of luck with a Y shape and or wedges.

Larry i do it roughly 12 times a day since 2004 can change a collet and cutter in it over in 20 seconds flat. Quicker for just same shank size cutter.
I use a 1lb ball ended hammer and hold the shaft close to the head. Slacken lead screw off once undone a further 3/4 to 1 1/2 revs, grab hammer hold about 3-4" on top and a short sharp fast whack marginally following through.
Using wedges will impart more pressure on bearings plus try and part at an angle than straight down! No choice on a drill chuck and have broke JT6 doing exactly that leaving the MT3 still in drill quil.

It really isn't necessary to have a HT steel drawbar. Studding is fine, especially if you use stainless which isn't much more expensive. If the thread is stripping you're making it too tight! No wonder collets get stuck.