Metallics JTSS29SS 10 x 1-1/4 in. Pan Head Square Drive Tapping Screws - 18-8 Stainless - Each

A #2 square (Robertson) bit, listed as driver size 2R. The recess measures 0.112 across the flats with a gaging depth of 0.060 to 0.075 inch, so a worn or oversized bit will cam out. The square recess has tapered side walls and a conical bottom, which is why a proper R2 seats fully and lets you drive one-handed overhead.

You can, but be aware of the trade-off. Metallics states that fastening stainless steel parts to aluminum or steel can create a galvanic couple, a form of corrosion, in some environments. Indoors and in dry locations that is rarely an issue. Outdoors, in coastal air, or anywhere with standing moisture, the dissimilar-metal contact is where corrosion starts, so an isolating washer or a matched-metal fastener is the safer call.

Type A tapping screws have a gimlet point, which is a sharp pointed tip that starts its own hole in thin sheet metal, so for light gauge sheet, electrical boxes, and duct you generally drive it straight in. Into thicker stock or any hard material you want a pilot hole. The thread is 12 threads per inch to ASME B18.6.4, and the screw is rated 48 lb-in minimum torsional strength, so don't exceed that on an impact driver or you'll snap heads.

No. The JTSS29SS stainless tapping screw is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. On a federally funded project with domestic-sourcing requirements, this part won't satisfy the spec.

These ship as a jar of 100, which is the order minimum. The jar weighs 0.87 lbs. If you need a different size or a different count, Metallics notes other sizes and quantities are available by request.

Metallics lists the field application as the electrical, plumbing, heating and air conditioning industries. In practice that means mounting boxes and straps, hanging duct and sheet metal, and securing equipment where the 18-8 stainless material is wanted for corrosion resistance in damp or washdown areas.