Provided is a surface-coated cutting tool having both high wear resistance and high fracture resistance and having an indicator function that significantly facilitates the determination of the usage of a cutting edge. A surface-coated cutting tool according to an embodiment of the present invention includes a substrate and a coating formed on the substrate. The coating includes a plurality of layers. A surface layer of the plurality of layers is a titanium boride layer made of Ti.sub.xB.sub.y (where x and y are expressed as atomic percentages and satisfy 1.5<y/x<2.5) and has a compressive residual stress of 0.1 GPa or more in absolute value.

Collet chuck 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, characterized by 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.