CRL Amazing Glazing 1" Belgian Threaded Diamond Countersink Glass Chippers Nibblers & Accessories This also lets you use

This also lets you use drills larger in diameter than will fit in the built-in retaining ring

1929782 (pad) and 2245171 (locking nut)

such as glass or stone

submerged joints (swimming pools and aquariums)

CRL Amazing Glazing 1" Belgian Threaded Diamond Countersink Glass Chippers Nibblers & Accessories This also lets you useMetal Bond Diamonds Straight Shank or Belgian Type Mounts Chip Free 90 Tapers This CRL Diamond Countersink features a medium grit diamond for grinding precise, chip free, 90 tapers into existing holes in glass. Versatile because it can be used on any hole size up to the maximum countersink diameter. Run at medium speeds, the countersink must be applied to the glass so it touches the circumference evenly. It can also be used on marble and granite.