Lipstick on a Pig
Lipstick On A Pig
We have seen it happen numerous times, where a customer purchases a set of our UP or EP (Ultra Precision or Extreme Precision) grade collets and still ends up with a lot of runout when they mounted them in their spindle or ATC tool-holders. In every case, when they went back and measured the bore of their spindle (or tool-holder) they found significant skew and radial runout.
In the accompanying video, our customer found that his ER20 spindle (manual tool change), after being fitted with one of our UP-grade collets, had 28µ (0.0011in.) TIR near the face of the collet and 96µ (0.0038in.) about 38mm (1.50in.) down the shank. This is enough runout to severely impact the life of a microtool or even break it at first contact. Needless to say, cut quality would also be negatively affected.
Subsequent measurements showed out-of-phase skew runout in the tapered bore of the spindle that, when projected out of the chuck, predicted the measured TIR.
video courtesy of S. Rosburg