5/16"-18 x 3" Flat Head 6-Lobe, T-40 Floorboard Screw Type F, phosphate

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The 5/16"-18 x 3" Floorboard Screw is a thread-cutting fastener designed for securing floorboards to subflooring by creating its own threads in wood (Type F). The flat head offers a flush, countersunk finish and 6-lobe T-40 drive is best for heavy-duty woodworking applications requiring high torque.The phosphate finish provides mild corrosion resistance.