Metallics QK19M 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 QK19M is a sharp point self-piercing and tapping screw, so it pierces and forms its own thread as it drives. Twin lead threads cut the driving torque, and the undercut under the head lets more of the thread engage. For harder or thicker base material a pilot hole is still the safer approach.

A 1/4 inch hex socket or nut driver. The head is hex with a measured width across flats of 0.244 to 0.25 inch and a head height of 0.096 to 0.11 inch. It also has a slotted drive, slot width 0.045 to 0.054 inch and slot depth 0.052 to 0.074 inch, so a standard flat blade works in tight spots where a socket won't fit over the head.

Not reliably on a head-size basis. Metallics notes that head dimensions on self-piercing screws differ from standard tapping screws, and that there is no single industry standard for self-piercing screw dimensions, so the published figures are a guide and deviations occur. If your spec or hole pattern depends on an exact head footprint, match the 0.244 to 0.25 inch width and 0.322 to 0.348 inch washer OD rather than assuming parity with a standard tapper.

No. The QK19M is listed as not Buy American compliant and not ARRA compliant, with country of origin reported as multiple. If your project carries a domestic sourcing clause, this fastener will not satisfy it.

It's a #8 diameter screw, 2 inches long, with 15 threads per inch. That 2 inch length is what you reach for when you're going through strut, insulation, or layered sheet metal rather than fastening skin to skin. Thread engagement starts right under the undercut head, so you get usable grip even on thicker stack-ups.

The head has an integral washer face, 0.322 to 0.348 inch outside diameter and 0.019 to 0.031 inch thick. No separate washer required for normal sheet metal work. It spreads the bearing load, but it is not a sealing washer, so for weather exposure you'd want a bonded neoprene washer screw instead.

The QK19M is steel with a zinc finish, made from AISI 1018-1022 steel. Zinc plating is an indoor/protected-location coating. For rooftop, exterior, or wet environments, specify a stainless or hot dip galvanized fastener rather than zinc plated steel.

Case hardness runs Rockwell C28-38, which is the range self-piercing sheet metal screws are heat treated to for cutting their own thread in sheet steel without snapping. It is a sheet metal fastener, not a concrete or hardened structural steel screw, so don't expect it to drive into heavy plate.

They ship in a box, with an order minimum of 1,000 pieces. Plan the buy as a bulk box rather than a small count, which suits a contractor stocking a truck or an MRO crib rather than a one-off repair.

Metallics lists it for the electrical, plumbing, heating and air conditioning industries. Typical use is anchoring boxes, straps, hangers and ductwork to sheet metal, where you want to drive with a 1/4 inch nut driver on a cordless and skip the pilot hole.