Collet Chuck

A guide bush with a collet chuck, which is mounted axially displaceably in a collet chuck holder, having a plurality of jaws which are radially movable with respect to one another and which, with their clamping faces, form a common receptacle for guiding a rod that is to be machined in a lathe, comprising:

• a blind hole which is routed in at least one jaw from the outer face, opposite the clamping face of the jaw, in the direction of the clamping face, with a blind-hole bottom which is delimited on the one hand by the clamping face and on the other hand by the blind hole and which, through wear of the clamping face, is configured to effect the formation of a through-hole indicating the wear of the collet chuck and
• a device communicating with the bottom of the blind hole of the collet chuck, the device being designed to output an alarm signaling the wear of the collet chuck when a through-hole is formed due to wear of the bottom of the blind hole, wherein the device is designed for applying compressed air to the blind hole, for detecting the air pressure in the blind hole and, in the event of a drop in air pressure detected due to the formation of the through-hole, for outputting the alarm signalling the wear of the collet chuck.