Diamond Drill Bit Hollow Core Drill Bit Set Diamond Coating Carbon Steel for Glass Ceramics Porcelain Ceramic Tile Granite Marble Porcelain Bottles DIY 10Pcs 6-30mm

Specifications: Quantity: 10 Pcs Size: 6mm / 0.23 ", 8mm / 0.31", 10mm / 0.39 ", 12mm / 0.47", 14mm / 0.55 ", 16mm / 0.62" ,18mm / 0.7 ", 20mm / 0.78", 22mm / 0.86 ", 30mm / 1.17"(6mm-30mm) Note: If you smell burning, back off! Either your speed is too high or the pressure you're applying is too much. You're drill bit should never be hot to the touch, not even warm. - Slowest speed - Coolant - Minimum pressure Nous: The general rule is the smaller the diameter of your drill bit, the faster drill speed you can use. The harder your material, the slower drill speed you should use. Packaged included: 10 pcs Diamond Coated Hole Saw Drill Bits