Metallics QK20M 10 x 1/2 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pre-drilling. The QK20M is a sharp point self-piercing and tapping screw, so it pierces and forms its own thread in sheet metal as you drive it. Twin lead threads keep driving torque down, and the screw is hardened to Rockwell C28-38 so the point holds up while it cuts.

Two options, because the head is a 1/4 inch hex with a slotted drive cut into it. Run it with a 1/4 inch hex driver or nut setter for speed, or back it out by hand with a #8 slotted blade. The slot measures 0.045 to 0.054 inch wide and 0.052 to 0.074 inch deep, so a standard cabinet-tip screwdriver seats properly.

It is a #10 diameter screw, 1/2 inch long, with 12 threads per inch. The undercut under the head gives you more usable thread engagement than a standard tapping screw of the same length, so at 1/2 inch it is sized for sheet metal and light gauge work (duct, box and strap fastening), not for thick stock.

No. The QK20M is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this screw will not satisfy it.

Head width runs 0.244 to 0.25 inch with a head height of 0.096 to 0.11 inch, and there is an integral washer measuring 0.384 to 0.414 inch outside diameter, 0.019 to 0.031 inch thick. That washer face spreads the load and covers a slightly oversized or torn pierce hole. Note that self-piercing screw heads are dimensioned differently from standard tapping screws, so the values are a guide rather than a fixed standard.

The QK20M is carbon steel (AISI 1018 to 1022) with a zinc finish, which is a dry-interior plating. It is intended for electrical, plumbing, heating and air conditioning work inside the building. For sustained exterior exposure or washdown areas, use a stainless or hot-dip galvanized fastener instead.

They come in a jar of 1,000 screws, which is the order minimum, with a shipping weight of 3.53 lbs. The jar footprint is 3.5 in by 3.5 in by 5.75 in, so it sits in a van bin or on a shelf without repacking. Other sizes and quantities are available by request.

A sharp point self-piercing screw like the QK20M punches through thin sheet and taps its own thread, which is faster on light gauge material and leaves no drill shavings. A self-drilling point with a drill flute is what you want once the steel gets heavier than the point can pierce. The QK20M's 1/4 inch hex head with a washer face also lets you drive it with a nut setter overhead, which matters on duct and strap work.