LDEXIN 2Pcs 45mm/1.78" Diamond Coated Drill Bit Porcelain Ceramic Glass Tile Porcelain Hole Saw Hollow Core Drill Bit Extractor Remover Tools(45mm/1.78inch)

They are often called Glass Drill or Tile Drill, but they are much more versatile since they are used to drill glass, tile bottles, ceramics, porcelain, ceramic tile, limestone, slate, marble, granite, light stone, and fiberglass. 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. Please always remember to use water for lubrication, or the diamond core drill will burn. Not for use on Concrete or for depths beyond about 1/2". Note: If you smell burning, back off! Either your speed is too high or the pressure you're applying is too much. Your drill bit should never be hot to the touch. 2Pcs 45mm/1.78inch Diamond Glass Drill Bit in a Pack Material: Metal, Diamond Particles Coated Hole Saw Diameter: 45mm/1.78inch Packing Weight:150g Packing Size:12x8x4.5cm