Metallics QK158M 8 x 1 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

The QK158M takes a 1/4 inch hex driver or a slotted bit, since the head is a hex washer head with a slot cut in it. Head width runs 0.244 to 0.250 inch across the flats, head height 0.096 to 0.110 inch, and the slot is 0.045 to 0.054 inch wide and 0.052 to 0.074 inch deep. The dual drive is handy on a job where you need a screwdriver to start or back one out in a tight spot a nut driver will not reach.

No. The QK158M has a sharp point and twin lead threads, so it pierces and taps thin sheet metal in one pass without pre-drilling. The twin lead thread also cuts driving torque, which matters when you are running hundreds of them overhead. For thicker steel, where a sharp point will skate or snap, a self-drilling point screw is the right call instead.

The QK158M ships as a box of 8,000 pieces, which is also the order minimum. The full box weighs 43.2 lbs and measures 7.25 x 6.25 x 6 inches. If you need a smaller count or a different diameter and length, Metallics makes other sizes and quantities in this self-piercing line to order.

Metallics lists the QK158M as both Buy American compliant and ARRA compliant, which is what a government, school district, or healthcare procurement office needs on file before a fastener goes into a federally funded job. Country of origin is listed as multiple.

Case hardness is Rockwell C28-38 on AISI 1018 to 1022 steel, which is what lets the point form its own thread in sheet steel rather than deforming. The finish is zinc plating on steel, so it is suited to dry interior work such as duct, strut, raceway, and track framing. Zinc plate is not a marine or sustained wet-exposure coating.

No, and this catches people. Metallics notes that self-piercing screw head dimensions differ from standard tapping screw dimensions, and there is no single industry standard for self-piercing screw dimensions, so the figures given (0.244 to 0.250 inch head width, 0.096 to 0.110 inch head height) are a guide and deviations can occur. If you are fitting into a counterbore or a tight recess with no clearance to spare, work to the upper end of those ranges.