mt3 chuck -stuck

[colin calverParticipant @colincalver]

[colin calverParticipant @colincalver]

Hi experts, When trying to get mt3 drill chuck out of mill, hitting drawer bar with mallet would not shift it, as has before, eventually had to hit with 7lb lump hammer, (draw bar suitably protected) it then relectantly came out after several hits. Question is 1-should tapers be put in cleaned AND oiled or clean and dry? and 2 – why should this happen?

[Tony Pratt 1Participant @tonypratt1]

Very cringe making thinking about having to use a 7lb hammer to get your chuck out. This has been discussed many times before on different forums, I believe the unwary overtighten the draw bar when using morse taper spindles and exert a massive gripping force as the taper has a shallow angle.

Morse tapers are generally regarded as self gripping ie doesn’t really need a drawbar for lathes and drilling machines but on some mills you have to hold and eject the taper with a draw bar.

I would say a clean and dry taper is best and don’t overtighten!

Tony

[DustyParticipant @dusty]

I was taught that you allways cleaned the socket and taper, then just before you insert the taper into the socket run it through or wipe it with your hand, the slight greasiness of your hand is enough to lubricate it. The drawbars function is to stop the chuck from falling out of the socket, nothing else, so it does not need to be tightened to excess i.e. just a little more than a nip up. If you put the taper into the socket while the machine is warm and slightly overtighten the drawbar, as the machine cools down (especially during the present cold weather) it will grip it like crazy. You are getting a degree of shrink fit. I try to make it a practice to remove tooling from the mill before I pack up for the day, this is not allways possible if you are in the middle of a job.

[JonParticipant @jon]

Lock the spindle and give a sharp whack.

If covering the drawbar up, its absorbing the impact.

 

Current machine MT3 was a real pig until recently. To give you some idea it s daily use is removing and changing collets and drill chucks around 8 times over 7 years!

 

The other mill MT3 has always been superb at removing collets etc within literally a few secs. Undo drawbar and back off 1 to 1 1/2 revs and sharp tap almost like an R8.

If you dont tighten the chucks up, the drawbar will work loose.

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