On Sat, 20 Jul 2013 01:36:05 -0700, Gunner Asch
wrote:

On Fri, 19 Jul 2013 08:21:22 -0700, Larry Jaques
wrote:

On Fri, 19 Jul 2013 07:18:03 -0700, Gunner Asch
wrote:

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

So there's a grasping mechanism in the spindle which grabs that
button? Or levers to wedge it upwards, seating the tapers together?
Got any photos of cutaways or exploded diagrams? They're always
easiest on my grokker.


A grasping mechanism.

Ill see what I can find for you.

One type..using balls

http://www.techniksusa.com/images200...rawbar_web.jpg

Best I could find in a couple minutes searching. Ill pull a page out
of a manual and scan it maybe tomorrow if you still dont get it.

OK, so a pressure on the top end of the drawbar compresses the springs
and gives room for the balls to float and release the retention knob?
By Jove, I think I've got it!

If you find exploded diagrams of other methods, I'd love to see them,
too.

--
Always bear in mind that your own resolution to
succeed is more important than any one thing.
-- Abraham Lincoln