Metallics JQK10 8 x 3/4 in. 1/4 Hex Head Slotted Sharp Point Self-Piercing & Tapping Screws - Steel Zinc - Each

No. The JQK10 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, which matters when you are running a lot of them overhead into duct or box flanges. For thicker structural steel you want a self-drilling point instead.

Either. The head is a 1/4 inch hex with a slotted drive across the top, so you can run it with a 1/4 inch nut setter or back it out with a flat blade screwdriver. The head measures 0.244 to 0.25 inch across and 0.096 to 0.11 inch high, and the slot is 0.045 to 0.054 inch wide by 0.052 to 0.074 inch deep. Driver size is listed as #8.

No. The JQK10 is listed as not Buy American compliant and not ARRA compliant, with multiple countries of origin. If your contract carries a domestic sourcing clause, specify a domestically produced fastener instead.

15 threads per inch on a #8 diameter, 3/4 inch long screw. That is the coarse twin-lead thread typical of sheet metal work, and the undercut under the head lets more of that thread engage the material.

It is case hardened to Rockwell C28-38 and made from AISI 1018-1022 steel, which is the standard range for tapping screws that have to form their own thread in sheet stock. Hard points on soft-steel screws are the usual failure mode, and this one is spec'd to the tapping screw material standard.

The JQK10 is zinc plated steel. Zinc handles indoor and normally dry conditions fine, which is where most electrical, plumbing and HVAC work happens, but it is not a stainless or a coated exterior fastener. For sustained wet or exterior exposure, step up to a corrosion rated fastener.

They ship in a jar of 100, and 100 is the order minimum. Jar weight is 0.43 lbs. Metallics notes other sizes and quantities are available by request.

There is an integral washer under the hex head, with an outside diameter of 0.322 to 0.348 inch and a thickness of 0.019 to 0.031 inch. That spreads the clamp load on thin sheet so the head does not pull through, and the undercut behind it gives more thread engagement.

They do not. Metallics states plainly 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. The published figures are a guide and small deviations can occur, so if you are matching an existing head profile exactly, work from the measured part.