In my 15+ years as a machinist, I don't recall running a BP that the key was left in. When using a manual drawbar, the collet is usually wedged into the spindle enough that the drawbar screws up and out of the collet and then requires a small peck on top of the drawbar to release the collet. And the power drawbars that I have used, usually have enough tension in the air powered mechanism atop the machine to force the collet out of the spindle when being removed. The wedging action of the collet being drawn into the spindle by either manual tightening of the drawbar or by a power drawbar tends to keep the collet from spinning. Its just a matter of personal preference I think. Removing the key won't cause any mechanical harm to the machine. |