Metallics QK17GRM 8 x 1-1/2 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Gray - Steel Zinc - Each

Either works. The QK17GRM 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) for a flat blade when you can't get a driver in. Head height runs 0.096 to 0.11 inch, so it sits low under a panel edge or a clamp.

No pilot hole. The QK17GRM is a sharp point self-piercing and tapping screw, so it punches its own hole and forms its own thread in thin sheet. That is what separates it from a standard tapping screw, which expects a drilled or punched hole first. Hardness is Rockwell C28-38 with AISI 1018-1022 steel, which is what lets the point bite without blunting. On heavier stock or structural steel, use a self-drilling point instead.

At 15 threads per inch on a #8 x 1-1/2 inch shank, the QK17GRM is a coarse twin-lead thread meant for sheet metal and soft substrates, not fine machine-thread work. The twin lead cuts driving torque, and the undercut under the head gives you more usable thread length than a standard tapping screw of the same nominal length, so more of that 1-1/2 inches is actually engaging material.

Yes, the head is a hex washer head. The washer outside diameter runs 0.322 to 0.348 inch and the washer section is 0.019 to 0.031 inch thick, so it spreads the clamp load over thin sheet instead of dimpling or pulling through. That makes it workable on light-gauge panel and trim without adding a loose washer.

These ship as a box with a 1000-piece order minimum, so the smallest purchase is the full thousand. Box weight is 7.1 lbs. Other sizes and quantities in the series are available by request if 1000 of this exact size is not what the job needs.

The QK17GRM is flagged compliant for both ARRA and Buy American in Metallics' product data. Country of origin is listed as multiple, so if your contract requires documented single-country origin on the specific lot, that is a submittal item to confirm with the shipment paperwork rather than something the catalog designation settles.

Be careful there. Head dimensions on self-piercing screws differ from standard tapping screws, and there is no single industry standard for self-piercing screw head geometry. Metallics publishes the QK17GRM figures (0.244 to 0.25 inch head width, 0.096 to 0.11 inch head height) as a guide, and deviations can occur. If your detail depends on an exact head profile, dimension off the actual part.

The head is gray, which is the point of it - it blends into gray enclosures, panel faces and painted sheet without a touch-up. The screw body itself is zinc-finished steel, so you get the gray head cosmetically and zinc plating on the shank.