[QUOTE=Geof;489558] If the air does not turn on quickly the eject cylinder moves slowly and does not develop enough impact to knock the tool out. QUOTE]

+1

The CAT 40 drawbar smacks the back of the retention knob. The clamp/unclamp piston has to build enough pressure to overcome the springs on the drawbar, plus accelerate the drawbar to give it that "umph" so it will actually impact the tool out of the tool taper.

And yea, after extended use especially during heavy cutting, the tool will tend to suck up in the taper a little more, makes it easier if the spindle gets hot. Then the tools are a little harder to eject, it's known issues with CAT and BT tooling.

MC