5/16-18 x 3 in. Six-Lobe (T40) Flat Head Thread Cutting Type F Floorboard Screw in Phos and Oil Finish (50 per Pack)

Floorboard screws are designed for attaching wood floors into truck trailers. The flat head design of floorboard screws provide a flush surface in countersunk holes. Also used in applications that require fastening to heavy-gauge sheet metal, aluminum, brass, cast iron and plastic. Made from hardened steel (Rc45 minimum case hardness). For best performance, the material in which the threads are cutting should be of a lower hardness than the RC45 screws by 10-20Rc. Pilot holes required.|9/32 in. pilot hole recommended|T40 driver bit size|Material: hardened steel (Rc 45 minimum case hardness)|50 per pack