Metallics QK19CCL 8 x 2 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pilot hole needed in sheet metal. The QK19CCL is a sharp point self-piercing and tapping screw, so the point pierces the material and the thread forms its own mating thread as it drives. Twin lead threads cut the driving torque. It is heat treated to Rockwell C28-38, which is what lets the point bite into steel rather than deform.

Either works. The head is a 1/4 inch hex measuring 0.244 to 0.25 inch across, so a 1/4 inch 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) for a flat blade when you cannot get a driver square to the work. Head height runs 0.096 to 0.11 inch, so it sits low under a cover plate or strap.

Metallics lists the QK19CCL as both Buy American compliant and ARRA compliant. Country of origin is recorded as multiple, which is normal for a fastener line produced at more than one plant. If your submittal package needs a mill-specific origin letter, ask for it with the order.

It is a #8 diameter by 2 inch long screw at 15 threads per inch. The 2 inch length is a lot of shank for sheet metal work, so it is aimed at jobs where you are reaching through a strap, standoff, or stack of material rather than fastening two thin sheets face to face. The undercut below the head gives you more usable thread engagement than a standard tapping screw of the same length.

Yes, it has an integral washer face: outside diameter 0.322 to 0.348 inch, thickness 0.019 to 0.031 inch. That bearing surface spreads load on thin sheet and covers a slightly oversized or previously used hole, so you are not adding a separate washer in the field.

They ship in a jar of 250 and 250 count is the order minimum, so this is a shop or truck-stock quantity rather than a loose-piece buy. The filled jar weighs 2.2 lbs.

The QK19CCL is carbon steel with a zinc finish, made from AISI 1018 to 1022 steel. Zinc plating is a dry-interior and light-duty corrosion finish. For sustained exterior exposure, wash-down areas, or coastal work, specify a stainless or hot-dip galvanized fastener instead.

Because self-piercing screws are not dimensioned to the tapping screw standard. Metallics states outright that head dimensions on self-piercing screws differ from standard tapping screws, and that no single standard governs self-piercing screw dimensions, so the published figures (0.244 to 0.25 inch head width, 0.096 to 0.11 inch head height) are a guide and small deviations can occur. If you are matching an existing head profile exactly, measure what is in the panel first.