The diamond particule coating on DRILAX hole saws give superior performance and lifetime. Please note our tools do not need center pilot holes. Center pilot hole drills are mostly for wood, metal, etc. This set is specially made for drilling holes in thicker materials such as granite counter-tops. You can drill 1 1/4″ to 1/38″ in depth with ease. Shank is 3/8″ - common electric or rechargeable drillers can be used. Electroplated diamond coating will wear off if the tool gets too hot. Never let your drill bit run dry. Here is how you could use water to keep the tool cool: a- You can build a mini water dam around the hole with plumbers putty. b- You can choose to spray water on the drill bit. c- Or you can use running water to cool the drill bit. EASY TO USE High Density Poly Insert Included - You can use it as a guide to keep the hole saw in position. We recommend using DRILAX Diamond Hole Saw Drill Guide. Center pilot drill bits are for wood, metal, etc.; Here is how you can keep the drill bit on target: a- You can make your own guide out of plywood - plastic or even a card board. All you need is to keep the drill bit in place until it makes the initial marks. You can also use the insert as a guide. b- You can start drilling at an angle, with the edge of the drill bit making a C slot and then getting the drill bit up to vertical. c- You can manually guide the drill bit with wet sponge. Please use protective gear.

• PREMIUM QUALITY LONG LASTING Diamond Hole Saw Drill Bit Tool Set in Elegant PU Zipper Storage Case, High Density Poly Insert Included - You can use it as a guide to keep the hole saw in position.
• SAVE OVER 80 Percent on MOST POPULAR 5 Sizes: 3/4", 1", 1-3/16", 1-3/8", 1-5/8" - Having these sizes available will help you cover almost all of your applications.
• SPECIAL FEATURE : These hole saws are 30 percent longer (deeper) than most competitors. You can drill through thicker materials with our tools. 1-3/8 inch counter-tops are no problem. Shank size is 3/8 inch for common drills.
• EXCELLENT RESULTS in Granite, Ceramic and Porcelain Tiles, Glass, Marble, Slate, and many types of Stones.
• WE ARE HERE TO HELP and REFUND YOUR MONEY.