Metallics QK16GRM 8 x 1-1/4 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Gray - Steel Zinc - Each

The QK16GRM takes a 1/4 inch hex driver or nut setter, and the head is also slotted so a flat blade works when you cannot get a socket in. The slot runs 0.045 to 0.054 inch wide and 0.052 to 0.074 inch deep, so a standard cabinet-tip screwdriver seats in it. Head width across the flats measures 0.244 to 0.25 inch and head height 0.096 to 0.11 inch.

No pilot hole. The QK16GRM is a sharp point self-piercing and tapping screw, so it pierces thin sheet metal and cuts its own thread. Twin lead threads cut driving torque, and the screw runs 15 threads per inch. Hardness is Rockwell C28-38 on AISI 1018-1022 steel, which is what lets the point pierce rather than skate. It is still a sheet-metal fastener, not a self-drilling screw for structural steel thickness.

There is an integral washer under the hex head, 0.322 to 0.348 inch outside diameter and 0.019 to 0.031 inch thick. That spreads the load on sheet metal and thin panels better than a plain hex head. There is also an undercut beneath the head, which gives you more usable thread engagement for a given 1-1/4 inch length.

The QK16GRM ships as a box with a 1000-piece order minimum, so a thousand is the smallest buy on this size. Metallics does make other sizes and quantities in the same hex head slotted sharp point self-piercing line available by request.

Both the ARRA and Buy American flags on the QK16GRM are marked compliant, which is what a government, school district or federally funded project submittal looks for. Country of origin is listed as multiple, so if your spec requires a single named origin on the paperwork, confirm the origin marking on the box you receive.

They are not meant to. Head dimensions on self-piercing screws differ from standard tapping screws, and there is no single industry standard for self-piercing screw dimensions. Metallics publishes the QK16GRM values as a guide, 0.244 to 0.25 inch head width and 0.096 to 0.11 inch head height, and deviations can occur. If you are matching an existing fastener for appearance or for a counterbore, measure what is in the job rather than assuming interchangeability.

The head on the QK16GRM is finished gray, which is why electricians reach for it on gray-painted panels, boxes and channel where a bright zinc head would stand out. The screw body itself is zinc-plated steel.

Zinc-plated steel is the finish here, which handles dry interior and protected locations. For sustained wet exposure, salt air, or direct weather, zinc plating is not the right call and you want a stainless or coated-for-exterior fastener instead.

A 1000-piece box of the QK16GRM weighs 6.08 lbs, and the carton measures 7.25 by 4.5 by 4.5 inches. Easy enough to stock several sizes on a service van without eating up shelf space.