Interior / Exterior Use
No Pre-Drilling Unless Material Requires
Starhead Recess / Non Stripping Heads
Can Be Used With Fibrous Materials
PHEINOX™ stainless steel screws are made from only the best grade of stainless steel wire, 305. The unique characteristics of the PHEINOX™ wire give our stainless steel screws unmatched performance, by maximizing both torque and increasing bending strength.
GRK’s R4™ self-countersinking screw has an under head with saw-blade like patented cutting teeth and six self-contained cutting pockets. Together these features act like 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 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.
GRK recommends PHEINOX™ 305 stainless steel screws for applications that require superior corrosion resistance in wet environments such as decks, boardwalks, pools, and hot tubs. PHEINOXTM 305 stainless is also recommended for use with cedar, red-wood and various other wood substrates that have higher acid content as well as for composite deck boards. PHEINOXTM 305 stainless steel screws are recommended for applications located more than 1 mile from the coast.