Information Diamond types include sintering, electric plating or brazing. Electric plated and brazed diamond is surface coated, attached to the surface of the cutting edge. The cutting edge is instantly aging when the diamond breaks off. Sintered diamond cutting edge contains diamond particles from inside to outside, to ensure that the edge is always sharp. Sintered diamond has the sharpening property but electroplated or brazed diamond can not be sharpened. Universal Shank Easily operate on the Angle Grinder. Or need an adapter for drill or other machine, such as hex, round shank etc.. Cannot be used on impact power tools.The speed should be controlled when drilling. The speed should not be too low, the recommended speed: 3000- 6000RPM. Sintered Diamond Core Drill Bits for Concrete Brick Block Stone Masonry Sintered diamond cutting edge contains diamond particles from inside to outside to ensure that the edge is always sharp. Sintered diamond has the sharpening property. Sintered diamond cutting edge is not surface coated. The edge always contains diamond. Cut clean and fast holes. Make drilling process much easier. Large clearance hole facilitates entrance of cooling water and escape of chips and other particles from drilling. Applications Can Drill accurate holes on concrete, masonry, brick, marble, stone, marble, glass, tile and other hard materials.When using a hand electric drill, make a mark on the cutting material in 45 degree angle. Then you can drill holes in vertical.Can be Wet or Dry use. To prolong its using life, it must be used with water for cooling and lubrication. Notices Use a small feeding force at the beginning of drilling, and then increase the downward pressure after positioning.When drilling through the work piece, the drilling feed speed should be slowed down and the force should not be large to avoid severe impact to break the hole wall.Add coolant during the drilling process to prevent breakage caused by high temperature. When opening the hole, Pay attention to wearing protective gloves, glasses, etc.