Abstract: A tool for cutting metal machining comprises one or several cutting insert seats (1), each one for an indexable cutting insert, each insert seat comprising a bottom support surface (10) and at least two side surfaces, which form a right angle with each other. One of these side surfaces comprises two side surfaces (12, 16), which are located at different distances from the bottom support surface (10), one of these being intended as a support surface for square cutting inserts and the other as a support surface for specially shaped hexagonal inserts. In this way, one and the same insert seat can accommodate either a square or a hexagonal cutting insert, which considerably improves cutting economy.