1.Core Cutter Drill Bit 17.5Mm Dia (Tct Cutter) Suitable For Kbm 40 D Magnetic Core Drilling Machine. 2.Core Cutter Drill Bit 21.5Mm Dia (Tct Cutter) Suitable For Kbm 40 D Magnetic Core Drilling Machine. Note: Sample To Be Got Approved By Consignee Before Supply. Makes: Broachcutter, Bosch, Black & Decker, Eibenstock, Yg-1 Only.