Metallics JTSS27SS 10 x 3/4 in. Pan Head Square Drive Tapping Screws - 18-8 Stainless - Each

A #2 square drive bit (listed as driver size 2R). The recess measures 0.112 inch across flats with a gaging depth of 0.060 to 0.075 inch, so a standard R2 Robertson bit seats properly. The recess has a square center opening with slightly tapered side walls and a conical bottom, which is why a worn or undersized bit will cam out.

The JTSS27SS is a Type A tapping screw with a gimlet point, which is the sharp pointed style made for thin sheet metal. It forms its own thread as it drives, so it works in thin gauge sheet without tapping. Thread count is 12 per inch to ASME B18.6.4. For thicker steel or structural material, a pilot hole is still the right approach because a Type A point is not a drill point.

They can. Fastening 18-8 stainless parts to aluminum or steel can set up galvanic corrosion in some environments, which is worth weighing on exterior or damp installs. In dry interior electrical work it is generally not an issue, and the 18-8 stainless gives you better rust resistance than a plated carbon steel screw.

No. The JTSS27SS is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your project carries a domestic sourcing requirement, this screw will not satisfy it.

Minimum torsional strength is 48 lb-in. Stainless is softer than hardened carbon steel, so set an impact or drill clutch low and let the screw tap rather than driving it home at full torque. That 48 lb-in figure is the floor the screw is built to, not a target.

They ship in a jar of 100, which is the order minimum. Other sizes and quantities are available by request if you need a different length or diameter in the same JTSS pan head square drive family.

Metallics lists the JTSS series for electrical, plumbing, heating and air conditioning work. Typical use is fastening plates, straps, covers and light sheet metal where you want a corrosion resistant screw and a drive that will not cam out overhead.