Metallics QK15W10M 8 x 1 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Gray - Steel Zinc - Each

Either works. The QK15W10M has a hex head measuring 0.244 to 0.25 inch across, so a 1/4 inch hex driver or nut setter seats on it, and the head is also slotted (slot width 0.045 to 0.054 inch, depth 0.052 to 0.074 inch) if you need to back it out with a flat blade in tight quarters.

No. The QK15W10M is a sharp point self-piercing and tapping screw, so it pierces and forms its own thread in sheet metal without a pre-drilled hole. Twin lead threads cut driving torque, and the screw runs 15 threads per inch on a #8 diameter, 1 inch long.

These ship in a box with an order minimum of 10,000 each, so it is a bulk buy rather than a handful. Metallics does offer other sizes and quantities by request.

No. The QK15W10M is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. For a federally funded project with domestic sourcing language, you need a domestically produced fastener instead.

The screw is heat treated to Rockwell C28-38 from AISI 1018 to 1022 steel, which is the normal case-hardened range for a tapping screw driving into light gauge sheet metal and studs. It is a zinc plated carbon steel screw, not stainless, so it is for dry interior work rather than exposed or corrosive locations.

Yes, there is an integral washer head with an outside diameter of 0.322 to 0.348 inch and a washer thickness of 0.019 to 0.031 inch, which spreads the clamp load over thin material. Head height is 0.096 to 0.11 inch, and there is an undercut below the head that gives you more usable thread engagement.

They are not. Metallics notes that head dimensions on self-piercing screws differ from standard tapping screws, and there is no single industry standard for self-piercing screw dimensions, so the published figures (0.244 to 0.25 inch hex across the flats, 0.096 to 0.11 inch head height) are a guide and small deviations can occur. Measure the screw you are replacing before standardizing on 10,000 pieces.

The head is listed as white over the zinc plated steel body. On exposed electrical or sheet metal work where the fastener head will be seen against a white or light panel, that reads cleaner than bare plating; where appearance does not matter, it has no functional effect.

Order it as Metallics QK15W10M, from the JQK series. It is a #8 diameter by 1 inch long self-piercing and tapping screw with 15 threads per inch, 1/4 inch hex washer head, slotted drive, sharp point, zinc plated steel.