Fine toughness and hardness, long service. Shank carbide insert wrench diy set lathe boring bar holder turning tool g4e7 sdncn 1616h11 shank diameter 16mm / 0.63in length 100mm / 3.94in. SDJCR 1616H07 Shank Diameter 16mm / 0.63in Length 100mm / 3.94in. Hard metal material, large application turning tool with premium quality carbide insert and wrench.