Metallics JSTSP33 12 x 1-1/4 in. Pan Head Phillips Tapping Screws - 18-8 Stainless - Each

Mechanically yes, but be aware of the corrosion risk. Metallics notes that fastening stainless steel parts to aluminum or steel can set up a galvanic couple in some environments. Outdoors, in damp mechanical rooms, or anywhere salt is present, that dissimilar-metal contact can eat the softer base metal around the screw. For dry interior electrical work it is routine; for exposed or wet locations, isolate the joint or match the fastener to the base metal.

The JSTSP33 is a Type A tapping screw with a gimlet point, meaning it comes to a sharp tapered tip and cuts its own thread as it drives. It is the classic sheet metal screw style, intended for thin sheet, sheet metal enclosures, and similar light-gauge material where a pilot hole is drilled or punched and the screw forms the mating thread. It is not a self-drilling screw, so it will not start its own hole in steel; you still need a hole sized for the #12 shank. Thread pitch is 11 threads per inch.

No. The JSTSP33 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic-content clause, these will not satisfy it and you need a domestically sourced fastener instead.

Rated at 83 lb-in minimum torsional strength. That is the floor the screw will hold before twisting off, and it matters because stainless galls and work-hardens, so an impact driver run wide open will find that limit fast. Drive these with a clutched driver or by hand and back off once the pan head seats.

A #3 Phillips driver. These #12 screws use the larger #3 recess, not the #2 bit most crews carry for #6 through #10 screws. The recess runs 0.246 to 0.259 in. in diameter and 0.141 in. deep, so a #2 bit will cam out and chew up the stainless recess. Put #3 bits in the pouch before you start the run.

They ship in a jar of 100, and 100 is the order minimum. Other sizes and quantities are available by request if a job needs a different length or diameter in the same JSTSP series.

Metallics targets this one at the electrical, plumbing, and heating and air conditioning trades. In practice that is sheet metal duct, strut and channel fittings, enclosure and panel work, hanger and bracket attachment. The 1-1/4 in. length gives enough thread engagement to go through a bracket plus sheet material, and the 18-8 stainless holds up in damp mechanical rooms where a plated screw would rust.