Metallics JTSS31SS 10 x 2 in. Pan Head Square Drive Tapping Screws - 18-8 Stainless - Each

A #2 square (Robertson) bit. The recess is specified as driver size 2R, measuring 0.112 inch across the flats with a gaging depth of 0.060 to 0.075 inch. The square recess has slightly tapered side walls and a conical bottom, so a worn or undersized bit will cam out of it.

Mechanically yes, but be aware of the metal pairing. Fastening 18-8 stainless screws to aluminum or steel can set up a galvanic couple and cause corrosion in some environments, especially wet or coastal exteriors. For dry indoor work it is a non-issue; for damp or exterior locations, isolate the joint or use a fastener that matches the base metal.

No. The JTSS31SS is not Buy American compliant and is not ARRA compliant; country of origin is listed as multiple. If your contract carries a domestic-sourcing clause, this part will not clear it.

The JTSS31SS is a Type A tapping screw with a gimlet point, which is the sharp, tapered point made to start in sheet metal and soft materials without a pilot. Thread count is 12 per inch, coarse and widely spaced, which is what you want in wood, plywood or thin sheet. In harder or thicker stock, a pilot hole keeps you from twisting the head off at the 48 lb-in minimum torsional strength.

48 lb-in minimum torsional strength. That is a hand-tool and clutch-set-driver number, not a run-it-in-on-high-impact number. Set the clutch on an impact driver or you will snap heads, particularly at 2 inch length where you are driving a long way into the substrate.

Head dimensions follow ASME B18.6.3-2013 and the threads follow ASME B18.6.4, so they interchange with any spec calling out a standard #10 Type A tapping screw. One caveat the manufacturer notes: dimensions for #9 diameter screws in this family fall outside ASME B18.6.4.

That is the intended use. Metallics lists this screw for the electrical, plumbing, heating and air conditioning trades, and the square recess is the reason: it holds the bit on an overhead or one-handed drive better than a Phillips of the same size. The 18-8 stainless body suits damp mechanical rooms and exterior enclosures, though watch the galvanic pairing if you are screwing into bare aluminum or steel in a wet location.

They ship in a jar of 100, and 100 is the order minimum. The jar runs about 1.25 lbs. Other sizes and quantities in the JTSS line are available by request.