Metallics JDS151 7 x 1/2 in. 1/4 Indented Hex Head Slotted Sharp Point Tapping Screws - Steel Zinc - Each

The JDS151 is a Type A tapping screw, meaning a sharp gimlet point that starts its own hole in thin metal without a pilot. Metallics lists it for light metal assembly such as electrical outlets, framing and other sheet metal. If you are fastening into thicker steel or need a blunt-point thread-cutting screw, a Type A is the wrong pick.

Both work. The head is an indented hex with a slot cut in it, and the head width measures 0.244 to 0.250 inch, so a 1/4 inch hex driver seats on it. Width across corners is 0.272 inch if you are reaching with a small wrench. The slot runs 0.039 to 0.048 inch wide and 0.040 to 0.054 inch deep, which takes a small flat blade for hand work in tight outlet boxes.

Dimensions follow ASME B18.6.3-2010 and the threads follow ASME B18.6.4. Material is carbon steel in the AISI 1016 to 1024 range, case hardened to Rockwell C28-38, with a minimum torsional strength of 30 lb-in. That combination is what keeps the head from twisting off when you drive it with a cordless.

No. These are listed as not Buy American compliant and not ARRA compliant, with country of origin reported as multiple. On a federally funded job with domestic sourcing requirements you will need a domestically manufactured fastener.

They ship in jars of 100, and 100 is the order minimum. If you need a different count or another diameter and length in the same head style, Metallics offers other sizes and quantities by request.

It is a #7 diameter, 1/2 inch long screw with 16 threads per inch. Head height sits at 0.080 to 0.093 inch, and there is an integral washer face measuring 0.302 to 0.328 inch across and 0.017 to 0.029 inch thick, which spreads bearing on thin sheet so the head does not pull through.

The JDS151 is steel with a zinc plated finish, which is a mild indoor corrosion coating. It suits dry interior electrical and sheet metal work. For wet, exterior, or corrosive duty, specify stainless or a hot dip galvanized fastener instead.

A jar comes in at 0.33 lbs, with package dimensions of 3 x 2.15 x 3 inches. Light enough that quantity buys stack easily on a van shelf.