The heads serial TSI and TSX with parallel or convergent spindles are suitable to mill and to chamfer teeth. Particular care has been drawn on scating and on disposal of the spindles bearing, because tools in hard metal are used to chamfer all gear teeth and they have to stand continuos strong crashes. The result has been a solid construction of good look and with reduced overall dimension. The body is in light alloy, the spindle supports in cast iron and the gear in heat treated steel.