GRK R4 Multi-Purpose Screw is a versatile fastener that delivers increased productivity for hundreds of applications. Its feature-rich design provides a fast and reliable connection every time. R4 Multi-Purpose Screws have a Climatek Coating for installation in both interior and exterior conditions where exposure to moisture is intermittent and is code-approved for use in treated lumber.
GRK's R4 self countersinking screw has a new underhead with saw-blade like cutting teeth and six self-contained cutting pockets. Together they act similar to a circular saw-blade, transporting the drill dust away from the edge of the screw hole while cutting a perfectly clean hole into even the most brittle materials without cracking any surface treatment. This design also further enhances the R4's versatility by allowing the fastener to be installed without countersinking into even the hardest woods. The screw head closes the hole off with precision, leaving no damaged fibers around the head.