Size(31C250BP40) 5/16-18 x 2-1/2 Black Phosphate T40
Special Features
SELF TAPPING TRAILER DECK SCREWS - Designed specifically for attaching wood floors into truck trailers, but they can be used in a number of different applications such as those involving fastening to heavy gauge sheet metal, aluminum, castings, cast iron, brass, and plastic.
MATERIAL - Hardened Steel (RC 45 Minimum Case Hardness) | BLACK PHOSPHATE & OIL COATING - Provides corrosion Resistance
For consistent performance, the material in which the threads are cut should have a lower hardness of at least 10-20 Rockwell points
1/4-20 x 2 1/2 inch Flat Head Floorboard Thread Cutting Screws, Type F, T30 Torx, Black Phosphate (100 Pack) - SOLD BY U-TURN FASTENERS
HIGH QUALITY Thread Forming Screws that won't let you down. These Screws require a pre-drilled hole, but they are able to cut their own treads into thick material. Can be used in a wide variety of base materials.