Metallics JTEKD15V 8 x 1-1/2 in. 1/4 Indented Hex Head Self-Drilling & Tapping Screws with Washer - #2 Drill Point - Steel Zinc - Each

A 1/4 inch hex driver. The indented hex washer head measures 0.244 to 0.250 inch across the flats and 0.272 across the corners, with head height of 0.096 to 0.11 inch. There is no slotted or Phillips drive to strip out, which is why these run well in an impact or screwgun.

The JTEKD15V is zinc plated carbon steel, which is a mild indoor/protected-location finish. For strut, panel boxes, conduit straps and interior metal framing it is the normal spec. For sustained outdoor exposure or a damp/corrosive environment, specify a stainless self-drilling screw instead.

The integral washer runs 0.322 to 0.348 inch outside diameter and 0.019 to 0.031 inch thick, giving more bearing surface than a plain hex head. That is enough to bridge an oversized or slotted hole in sheet metal, but it is a bare metal washer, not a bonded sealing washer, so it will not weatherproof a penetration on its own.

Minimum torsional strength is 42 lb-in with case hardness of Rockwell C32-40. Metallics notes minimum torques are the same for stainless and steel self-drill screws, and drill time runs about 2.5 seconds through a 1 mm plate. Keep the driver at moderate speed and steady pressure; the usual cause of snapped heads is over-torque after the screw has seated.

Both the Buy American and ARRA fields on the JTEKD15V are marked compliant. Country of origin is listed as multiple, so if your submittal requires a single named origin for the lot, request documentation for the specific production run.

They ship in a jar with a 500 count order minimum, and the packed weight is listed at 3.9 lbs.

18 threads per inch, UNC, to SAE J78 - 2013. That is the standard #8-18 self-drilling thread, so it cuts its own mating thread in sheet steel rather than needing a pre-tapped hole. Head dimensions follow ASME B18.6.3-2010.