Metallics JQK20V 10 x 1/2 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pilot hole needed. The JQK20V is a sharp point self-piercing and tapping screw, so it pierces thin sheet metal and cuts its own thread as it drives. Twin lead threads cut the driving torque, and the undercut under the head lets more thread engage the material.

With a 1/2 inch overall length and 12 threads per inch, the JQK20V is a sheet metal fastener, not a structural one. Figure on thin gauge steel and light sheet work where the point can pierce and still leave thread engagement behind the panel. For heavier stock or thicker stack-ups, step up to a longer screw or a self-drilling screw with a drill point.

The JQK20V is flagged compliant for both Buy American and ARRA. Country of origin is listed as multiple, so if your specification requires a single documented origin, request the mill paperwork for the lot you receive.

It takes a 1/4 inch hex driver or socket, and it also has a slotted drive so a flat blade screwdriver works where a socket will not reach. The hex head measures 0.244 to 0.25 inch across and 0.096 to 0.11 inch high; the slot runs 0.045 to 0.054 inch wide and 0.052 to 0.074 inch deep.

There is an integral washer face under the head, 0.384 to 0.414 inch outside diameter and 0.019 to 0.031 inch thick. It spreads the clamp load on sheet metal; it is a steel washer face, not a rubber EPDM sealing washer, so it does not seal a weather exposed hole. The finish is zinc plated steel, which suits dry interior electrical work.

They ship 500 to a jar, and 500 count is the order minimum. Plan on buying by the jar rather than by the piece.

No. Head dimensions on self-piercing screws differ from standard tapping screws, and there is no single industry standard for self-piercing screw dimensions. The figures given for the JQK20V (head 0.244 to 0.25 inch wide, 0.096 to 0.11 inch high) are a guide and small deviations can occur. If you are matching an existing countersink or a tight clearance hole, measure what is already in place.

Carbon steel to AISI 1018 through 1022, case hardened to Rockwell C28-38, with a zinc plated finish. That hardness is what lets the point pierce sheet steel without the threads stripping. It is not stainless, so avoid wet or corrosive locations.

A jar of 500 JQK20V screws weighs 2.65 lbs and measures 3 x 3 x 3.6 inches, so it drops into a van bin or gang box without taking much room.