Originally Posted by
Willbird
Before they retro the new controls on the machines used the old pin reader to discern the tool numper from feeling the rings on the toolholder, they would get chips in them and do some funky crap :-)....and the rings were such a PITA to change that a toolholder once it was Tool #1 pretty much stayed Tool #1 forever :-)....there was a special part that screwed into the back end of the toolholder so that the tool was PULLED into the spindle, we only used them on endmills...if you didnt use one a large endmill would get sucked out of the straight collet spindle by the helix on the cutter.