Abstract: A machine tool bit, such as a tool for drilling, milling, reaming or tapping or the like comprising a work portion (71) and a shank (73) extending from the work portion. The shank (73) is provided with one or more regions of reduced mechanical torque strength. Such regions can be for example, a reduced diameter (74), axial or longitudinal slots (84, 114), reduced cross sectional area (97), bores (94), annular notch or groove (63, 65), or a slot. The shank is preferably constructed with these features such that the transverse stability of the tool bit is greater than a machine tool bit in which an equivalent reduction in mechanical torque strength is achieved by a mere reduction in diameter of the shank. Technically, the Polar moment of inertia (resistance to torsion) of the modified shank is greater than the polar moment of inertia of a shank with a mere reduction in diameter of the shank.