Product Name: Diamond tip masonry bit, Stone cutting bits, Granite hole bit Hole/Outer diameter: 13, 16, 20, 25mm (1/2", 5/8", 3/4", 1") set Excellent for making clean and accurate hole on stone, granite, marble, tile, glass Start drill at 45 degree to surface and align to 90 degree as hole forms NOT have center pilot drill, it will fit handheld or upright drillers JINGLING 4Pcs 13 16 20 25 mm Diamond Coated Hole Saw Drill Bits Set for Stone Granite Marble Ceramic Product Specification Product Name: Diamond tip masonry bit, Stone cutting bits, Granite hole bit Hole/Outer diameter: 13, 16, 20, 25mm (1/2", 5/8", 3/4", 1") Shank diameter: 6.5-8mm Rim thickness: 1.3mm Drilling depth: 29mm Quantity: total 4 Pcs Features: Brand New & High Quality Easy to use, Good Performance and long life Excellent for making clean and accurate hole on stone, granite, marble, tile Works better with a electric drill( Excluding in this item) Drilling speed: Drill a Holes In Seconds Use with water as a lubricant Quick Tips 1. Please add water for coolant and drill slowly 2. Start drill at 45 Degree to surface and align to 90 Degree as hole forms 3. Never use drills while machine is in hammer action 4. Holes Require No Futher Work As Cutting Is Clean The Diamond Hole Saw Does NOT Have Center Pilot Drill There is no need for a Pilot Drill Bit, because pilots are not safe for glass/stone How to use a hand drill to drill holes in the glass/tile/stone? Step 1. The bit on the glass/tile/stone 45 degree, open a half-moon notch on it Step 2. Slowly up the bit to 60 degrees, and then gently drill Step 3. Reached 90 degrees, continue to drill Step 4. Drill through the glass/tile/stone finally, the technique requires a "wobble" of the drill rather that steady pressure straight on We Can List Any Size( Hole Diameter from 6mm - 160mm) & Amount Of This Product