Fasten wood to sheet metal while reducing stripping and pull-out. The dual threads on these screws grip both materials at the same time, so they install quickly, require less torque, and resist vibration. Also known as trailer floor screws, these screws are often used to fasten wooden boards to metal trailer frames. With a deep six-lobe opening, Torx drives handle more torque than slotted, Phillips, and hex drives. The flat head deters snags.

Drill a pilot hole slightly smaller than the screw to prevent splitting. Length is measured from the top of the head.

Reverse threads pull stray material inward instead of letting it bulge out to the surface. The flat underside of the pancake head creates a strong hold without the need for a countersunk hole. The Torx drive handles more torque than slotted, Phillips, and hex drives.

The screw drill tip acts as a built-in pilot, though pilot holes are still recommended near edges to avoid splitting. Length is measured from the top of the head.