Just to clarify, and simplify matters here--

Well, sort-of g The way I read your description of 1 and 2 below is yet
another version of a self-ejector mechanism. Your description suggests that
the only part of the tailstock "screw", as you call it, that hits the end of
the live center (I'll just use this example from now on to make it easier)
is at the center (of whatever diameter) of it's end shank. Is that a
correct reading of your comments below? If you have a hole in the bored
live center that's bigger than that mechanism, then I can certainly see the
live center passing right over it. This, of course, doesn't mean that every
live center that has a hole bored through it will not self-eject as George
blanketly stated.

What I'm talking about is what's most often found these days and that's
where the self-ejector mechanism acts very much the same but makes contact
with the outermost ring of the live center end shank. It doesn't matter what
size hole is bored (within reason ... you *could* have a 1mm sliver of metal
ring and it might slip past the mechanism a little but eventually the taper
would catch up to it and hit the mechanism anyway g) into that live center
as long as the shank is long enough to reach that self-ejector mechanism
when retracting the whole thing.

The essence of it is the same (retracting causes what's inside the morse
taper to stop retracting with the rest of the female morse taper) but it's
the details that matter most and affects what will and what will not
self-eject. Can you provide a picture or drawing of the exact mechanism?
I'll do the same of at least one version of self-ejector tailstock mechanism
that I've worked with on wood lathes and post it on abpw. Then we can
compare.

- Andrew




1.) The "self-ejector" you speak of is nothing more than the end of the
tailstock's feed screw which hits the end of the morse taper shank when
the tailstock ram is retracted.
2.) If a tailstock center is hollow, and the hole is bigger than the
screw, then of course it won't eject.
3.) The extension at the end of many morse tapers is called the tang, it
fits in a slot inside the drillpress spindle to hold the shank from
rotating in the spindle.


Ken Grunke
SW Wisconsin
http://www.token.crwoodturner.com/
Member, Coulee Region Woodturners AAW chapter
http://www.crwoodturner.com/