GRK's R4™ multi-purpose self-countersinking screw has six self-contained cutting pockets which act like a router and transport the "drill dust" away from the edge of the screw hole.
Made from PHEinox ™ hardened stainless steel with a Star Drive
Widens the countersink hole only around the head shape. The head top closes the hole exactly, leaving no damaged fibers around the wider area of the head.
Pre-countersinking is no longer required, it is done by the screw itself
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