A bore serration for locking externally serrated inserts (3) against rotation, with the external serration (4) comprising several teeth (5), and particularly for use with components made of hard, brittle materials, includes an arcuate serration (10) featuring arcuate recesses (7) produced by plunge or circumferential surface milling. Each of the recesses positively accommodates at least two teeth (5) of the outer serration (4) of the threaded insert (3). The arcuate serration can be produced with high dimensional accuracy without damaging the workpiece and with reduced wear of the tool, and ensures a long service-life of the threaded insert.