On Dec 24, 6:17*pm, "Grumpy" wrote:
"Bill Noble" wrote in message

...



"

For us in the metric world ,do you have a metric equivalent of 1 grunt?

1 grunt = 3.67 centiheaves

** Posted fromhttp://www.teranews.com**

Thank you Bill. That was the conversion factor I needed



With a #3MT I'd begin by torquing to 20 ft-lbs, and see how it goes.

Due to size restrictions on my mills I use collets exclusively for
endmills...

My vertical and horizontal mills have #2 and #3 MT respectively, and
the #2 is quite hard to release without the jacking arrangement
supplied by Emco Maier.

Strangely the #3 MT is fairly easy to release, a sharp whack with an
aluminum rapper and it is loose. The #3 MT collets were imports
bought from Busy Bee in Canada. While the tapers are OK some of the
bores were a few thou. oversized. With these I use a sleeve bent up
from appropriate thickness shim stock... The complete set of #3 MT
collets from 1/8" to 3/4" cost less than $80 20-odd years ago and I
didn't quibble about this defect.

The vertical head for the H-mill has a taper I was never able to
identify. The large end is about .025" larger in dia. than a #2 MT
and with a different taper/inch. I tried B&S #7 but no joy. Finally
I machined a batch of collets and shanks from 4140 to solve that
problem. However, this taper is an absolute bear to release. I used
an aluminum rapper and one project where I had to change cutters often
my hand got really sore. Didn't improve the bearings, either; they
now require replacing.

I solved the releasing problem by changing the draw bar, a grade 5
3/8-16UNC hex head bolt 7" long, into a jacking-type draw bar. To do
this it is necessary that the draw bar hole in the spindle be
significantly smaller than the small end dia. of the taper, ie. a step
is required from the bottom dia. of the taper bore to the draw bar
hole. Further, the taper bore must be at least 1/2" deeper than the
reach of the small end of the collet. By fastening a sleeve to the
draw bar such that it bears against this step while unscrewing it, a
jacking action is produced that pushes the collet from the spindle
taper.

Considerable torque is required to push out the collet... I use two
wrenches, one on the draw bar and one on the pre-load adjusting nut
(really two nuts torqued against each other). Of course the cutter
drops out of the collet, but I place a block of wood on the table to
prevent this. This system works quickly and easily and I can
recommend it strongly where it can be retro-fitted.

Wolfgang