Abstract: This disclosure relates to a boring head having two support ledges and a cutter that may be rotated when the cutting edges become worn so as to provide new cutting edges. The cutter is developed as an irregular hexagon the sides of which form a section of the sides of two equilateral triangles which are superposed on each other around an acute angle. The boring head includes a recess for the cutter having contact surfaces against which at least one of rake surfaces behind the cutting edges will bear so as to fix the cutter in a predetermined operating position in which one of the cutting edges cooperates with the two support ledges to provide centering of the boring head in a bored hole.