Diamond Tile Hole Saw with Centering Drill, Hard Brazed Diamond Drill Bit for Porcelain, Ceramic, Glass, Granite, Tile, Stoneware, Marble (140mm)

Diamond Tile Drill Bit - Dense and uniform diamond grain with vacuum welding technology for superior performance and longer life. Cut a precise and perfect hole: when the center pilot drill is loosened, you can loosen the screw in the shank to adjust the position of the drill bit and tighten it to continue drilling FAST & EFFECTIVE - Thick and even diamond coating for quick and effortless cutting. The large through-hole on the side allows water to retain cooling and easily remove chips. Instructions for use: Hold the drill bit vertically and use water to keep the hole cool when tightening. If the positioning guide is the screw bit is loose, you can use an allen wrench to loosen the screw in the rod, adjust the positioning guide and pull the screw to drill. Recommended speed: about 500-800 rpm.