releasing tapers

OK Hopper, I'll bite...

'...a different kettle of fish...' Very good! Clearly a sly pun, alluding to the Poisson ratio, which is of central relevance to what I was rambling on about!

Clearly, following a whack on the little end, the outwards deformation of the inserted male member (can I say that on this forum?) in the female socket will be miniscule, but would be detectable with a strain gauge on, say, the outside of a tailstock barrel. A compression wave will indeed travel through the tool (and socket): (elastic) deformation will not be confined to the tang. And, of course, whacking the thing (usually) gets it out, so any transient increase in the friction holding the things together will be overcome. However, given Poisson's insight into deformation mechanisms, pulling things out of tapers should be easier than pushing - although perhaps less practicable. That was my message - for what it's worth.

Anyone who has used a Clarkson 2MT collet milling chuck, with its 'steadying ring', will know how readily tightening the ring can release the taper. Ideal geometry for release.

I'm not trying to labour a point here, nor wishing to disagree with anyone - just indulging in a bit of theoretical whimsy - but I always cringe when anti-friction-bearing-supported bits of machine get attacked by hammers. Unfortunately, often there's no sensible alternative.

Myford do not construct their tailstocks to use the tang, if the taper lets go the drill spins. This has happened to me a couple of times when drilling something grabby that the drill has pulled it self into and released the taper, this has done no harm at all to the taper, the taper shank and tailstock taper have both been in A1 condition when this occurs. I think it may reinforce the theory that pulling a taper apart is very effective.

Mike

Edited By Mike Poole on 13/02/2019 10:21:02

I never cease to amaze myself. An unconscious genius, I tells ya.

Probably best not to add complication to the tang discussion by mentioning 'use-em-up' sleeves.

Wish I hadn't.

Agreed. The tiny MT1 taper on my old Drummond M-Type tends to let go occasionally when the old Flagellator is pushed hard. So much so that the ancient drill chuck that came with it finally would no longer grip. All the wear, corrosion and dents fom over the years were on the taper shank on the chuck. Inside of the tailstock barrel seems just fine. As pic posted way above shows, new chuck with new taper shank will hold a 1" drill firm without slipping. I don't think a spinning taper every now and then is a catastrophic problem.