Material: 45# steel . Accuracy: 0.015mm, Hardness: 50 HRC . For the usage of Morse taper shank, taper shank drills, reamers reducing. Adopts overall quenching process, long life, lasting, strong shock-resistance. Used to convert spindles to larger or smaller tapers and extend the spindles of drill presses, radial drills, boring mills and turret lathes.