Metallics QK1610M 8 x 1-1/4 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pilot hole. The QK1610M is a sharp point self-piercing and tapping screw, so it pierces thin material and forms its own thread as it drives. Twin lead threads cut the driving torque, which is what makes it practical to run thousands of them by power driver in sheet metal and light-gauge work.

The head is a 1/4 inch hex with a slotted drive, so a 1/4 inch hex socket or nutsetter is the fast way to run it, and a flat blade works in the slot when you cannot get a socket in. Head width measures 0.244 to 0.25 in. and the slot is 0.045 to 0.054 in. wide by 0.052 to 0.074 in. deep, so bring a thin-tip blade rather than a cabinet tip.

It is a number 8 diameter screw, 1-1/4 inches long, with 15 threads per inch. The 15 TPI count comes from the twin lead thread form used on self-piercing screws, so it will not match the thread pitch of a standard #8 tapping screw if you are trying to run it into an existing tapped hole.

The QK1610M is carbon steel with a zinc finish, which is a mild indoor corrosion coating, not a marine or exterior-exposure plating. It is fine for dry interior electrical and sheet metal work. For wet, coastal, or treated-lumber contact, specify a stainless or hot-dip galvanized fastener instead.

These ship as a 10,000 piece box, which is the order minimum. It is a contractor and MRO bulk quantity rather than a small hardware pack, so it suits standing stock for sheet metal, strut, and electrical rough-in work rather than a one-off repair.

The QK1610M is flagged compliant for both Buy American and ARRA. Country of origin is listed as multiple, so if your agency or institutional spec requires a documented single country of manufacture per lot, request that documentation against the shipment you receive.

Case hardness runs Rockwell C28-38, and the wire is AISI 1018 to 1022 low carbon steel. That is the normal range for a piercing screw: hard enough at the point to pierce light-gauge steel, with a core that resists snapping off in the hole. It is not a structural fastener and carries no shear or pull-out rating.

The hex head has an integral washer face, 0.322 to 0.348 in. outside diameter and 0.019 to 0.031 in. thick, which spreads the bearing load on thin sheet so the head does not pull through. It is a steel washer face, not a bonded sealing washer, so it will not weatherproof a penetration on its own.

Head height is 0.096 to 0.11 in., so it sits close to the surface, and there is an undercut beneath the head that gives you more thread engagement in the material. Worth noting that self-piercing screw head dimensions are not the same as standard tapping screw heads, so if a cover plate or channel has a counterbore sized for a conventional #8 tapping screw, check the fit first.

The box runs 60.3 lbs at roughly 7.25 x 6.25 x 6 in. per the published product dimensions. Plan on a hand-carry weight that one person can manage but will not want to walk up a ladder, so decant into a pouch or bucket on the job.