On Fri, 19 Jul 2013 05:57:31 -0700, Larry Jaques
wrote:
On Fri, 19 Jul 2013 05:33:17 -0500, Karl Townsend
wrote:
...
How is the CNC drawbar engaged? (curious) I thought drawbars were
just glorified, dual-threaded long bolts which engaged the bit from
the top, drawing it into the tapered spindle hole.
power drawbars have splined ends with points on the end of the
splines. There's a female mating spline on an electric impact wrench
and an air cylinder to drop it in place.
OK, that covers the top end, but what about the bottom? Are the bit
adapters tapered and do they have threaded tops like their manual
counterparts? I don't yet grok the mating method, -especially- after
seeing the spindle parts you showed. I only saw female bottoms, if you
will. (quiet, Mikey. 
http://www.ebay.com/itm/Emuge-CAT-40...-/261218374005
Look for the round gizmo sticking out of the top end of the tool
holder.
And a slightly different type
http://www.ebay.com/itm/SECO-EPB-GRA...-/181175831504
This is a pull stud that gets screwed into the end of a tool holder
http://www.shop.yourtoolingstore.com...45PullStud.jpg
Deep 7/8" impact socket and pneumatic impact wrench, Karl. Use a
large diameter hose and high pressure air for maximum torque. Try it
both ways to rule out left-hand threads. Maybe wedge an old bit in
the collet to slow down the turning if it slips on you.
Wish I'd ask you BEFORE I broke it 
I'm glad to share my vast (2+ hours) experience on milling machines
with you.
G
--
""Almost all liberal behavioral tropes track the impotent rage of small
children. Thus, for example, there is also the popular tactic of
repeating some stupid, meaningless phrase a billion times" Arms for
hostages, arms for hostages, arms for hostages, it's just about sex, just
about sex, just about sex, dumb,dumb, money in politics,money in
politics, Enron, Enron, Enron. Nothing repeated with mind-numbing
frequency in all major news outlets will not be believed by some members
of the populace. It is the permanence of evil; you can't stop it." (Ann
Coulter)