MT2 Carbide Tipped, Half-Notched Dead Center ~ Made of tool steel, hardened and ground. ~ +/- .0002″ TIR ~ Overall length (L) is 3.9″ ~ Height of the notch (h1) is .43″ ~ Widest diameter of the taper (H) is .70″ ~ D is 17.78mm. Made of tool steel, hardened and ground. +/- .0002″ TIR Overall length (L) is 3.9″ Height of the notch (h1) is .43″ Widest diameter of the taper (H) is .70″ ~ D is 17.78mm.