Metallics JQK1V 7 x 1/2 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No pilot hole. The JQK1V is a sharp point self-piercing and tapping screw, so it pierces thin sheet metal and forms 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. For thicker steel, where a sharp point cannot pierce, you want a drill point (self-drilling) screw instead.

A #7 diameter by 1/2 inch long screw with 16 threads per inch. That 1/2 inch length is short on purpose, enough to pierce and grip sheet metal without leaving a long point sticking out behind a panel or into a wiring cavity. If your stack-up is thicker than the thread can clear, step up to a longer length in the same series.

Two options, which is the point of the combination head: a 1/4 inch hex driver or socket, or a flat blade screwdriver in the slot. Head width measures 0.244 to 0.25 in. with a head height of 0.08 to 0.093 in. The slot runs 0.039 to 0.048 in. wide and 0.04 to 0.062 in. deep, so a standard cabinet-tip flat blade seats in it. In a panel or box where a nut driver will not reach, the slot gets you out of trouble.

Yes, the head carries a built-in washer section with an outside diameter of 0.322 to 0.348 in. and a thickness of 0.017 to 0.029 in. That spread distributes clamp load so the head does not pull through thin sheet, and it means you are not stacking a loose washer on the job. Note that self-piercing screw head dimensions differ from standard tapping screws, so a trim ring or hole sized for a standard tapping screw head may not match.

The JQK1V is steel with a zinc finish, which is a dry indoor-use plating. It handles interior electrical work, panel and enclosure assembly, and framing in conditioned space. For wet, exterior, or corrosive locations, specify stainless or a hot-dip or mechanically galvanized fastener instead; plain zinc will bloom and eventually rust through in standing moisture.

They ship in a jar, with a minimum of 500 count. That is the standard quantity for this item, so a van-stock or shop-bin buyer gets a full jar rather than a loose handful. The packed jar weighs 1.6 lbs. Other sizes and quantities in the series can be requested.

Metallics lists the JQK1V as both Buy American compliant and ARRA compliant. Country of origin is recorded as multiple, which is normal for a fastener line run from more than one mill, so if your specification requires documented domestic origin on the specific lot, request lot documentation with the order rather than relying on the line-level flag.

It is case hardened to Rockwell C28-38 and made from AISI 1018 to 1022 low carbon steel, which is the standard combination for a screw that has to form its own thread without the point rolling over. That hardness is also why you should not over-torque it with an impact driver; the thread it cuts is the thread you get, and snapping the head off in a piece of sheet metal is the common failure.

JQK1V, from the Metallics JQK series of self-piercing and tapping screws. The JQK family covers the hex head slotted sharp point configuration across sizes, so when you reorder, the JQK prefix plus the suffix identifies the diameter and length combination. Keep in mind there is no single industry standard for self-piercing screw dimensions, so published head and washer figures are a guide and small deviations occur between runs.