Metallics QK168M 8 x 1-1/4 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pilot hole. The QK168M is a sharp point self-piercing and tapping screw, so the point pierces thin sheet metal and the threads form their own mating thread as it drives. Twin lead threads cut the driving torque, which matters when you are running hundreds of them overhead. For thicker or harder stock a self-drilling point screw is the better choice.

The QK168M ships as a box with an order minimum of 8,000 pieces, so it is a bulk, production-quantity item rather than a shop handful. Metallics does make other sizes and quantities available by request if 8,000 of this size is more than the job needs.

Yes on both counts. The QK168M is flagged Buy American compliant and ARRA compliant, which is what a public works or federally funded electrical submittal typically asks for. Country of origin is listed as multiple.

Two ways to drive it. The head is a 1/4 inch hex with a slot, so a 1/4 inch hex nutsetter or a flat blade screwdriver both work. Head width measures 0.244 to 0.25 in. and head height 0.096 to 0.11 in., with a slot 0.045 to 0.054 wide and 0.052 to 0.074 deep. The hex socket is faster for production runs; the slot is there for the odd screw you cannot get a driver on straight.

Material is AISI 1018 to 1022 low carbon steel, case hardened to Rockwell C28-38, which is what lets the sharp point pierce sheet without rolling over. Finish is zinc plating, so it suits dry interior and sheltered work. Zinc plate is not a marine or exposed exterior coating, so for permanently wet or outdoor locations specify a stainless or heavier coated fastener instead.

15 threads per inch on a #8 diameter, 1-1/4 inch long screw. There is an undercut area beneath the head, which lets more of the screw length carry thread instead of losing it to a shoulder, so you get greater thread engagement in thin material than a comparable screw without the undercut.

Treat the published figures as a guide, not a hard standard. Head dimensions on self-piercing screws differ from standard tapping screws, and there is no single industry standard for self-piercing screw dimensions, so deviations from the listed head, slot and washer ranges can occur. Where a detail depends on an exact head height or washer diameter, verify against a sample from the box you receive.

The head carries an integral washer face measuring 0.322 to 0.348 in. outside diameter with a thickness of 0.019 to 0.031 in. That bearing surface spreads load on sheet metal and keeps the head from pulling through thin stock, so you do not need to add a separate flat washer.

A box runs 47.06 lbs, measuring 11.5 in. long by 11.5 in. wide by 10.75 in. high. Plan on a two hand lift or a cart if it is going up a ladder or into a van with the rest of the day's material.