The present invention relates to a cutting tool insert, solid end mill, or drill, comprising a substrate and a coating. The coating is composed of one or more layers of refractory compounds of which at least one layer comprises a cubic (Me,Si)X phase, where Me is one or more of the elements Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and Al, and X is one or more of the elements N, C, O or B. The ratio R=(at-% X)/(at-% Me) of the c-MeSiX phase is between 0.5 and 1.0 and X contains less than 30 at-% of O+B. This invention is particularly useful in metal machining applications where the chip thickness is small and the work material is hard e.g. copy milling using solid end mills, insert milling cutters or drilling of hardened steels.