"Marty Escarcega" wrote in message
...
Rex the Wrench wrote in
:

With the top nut installed on the spindle, loosening the drawbar
causes the shoulder on the drawbar to come up hard against the nut
which forces the collet or tool holder to unseat from the spindle. My
#645 Index (#9 B&S taper) and my Bridgeport "M" head (#7 B&S taper)
are both set up in a similar fashion.

Rex the Wrench

Rex, is the drawbar something more than a common drawbar?
Must be?

The drawbar has a reduced size hex on the top which leaves a shoulder. The
drawbar is 7/16 dia, the shoulder is about 3/4" dia and ~3/8" tall, then it
reduces to about a 1/2" square for the last inch or so. The nut that screws
on the top of the spindle just clears the 3/4 dia then has a 1/2" hole in it
for the hex to pass through. So in operation as you tighten the drawbar the
shoulder snugs up against the spindle and pulls in the collet. When loosing
the drawbar backs out of the spindle till it hits the nut capturing the
shoulder and the collet is forced out. Don't quote me on the dimensions but
there close. I could post pictures if needed.
lg
no neat sig line