Metallics JTSS9SS 8 x 1 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 inch across flats with a gaging depth of 0.060 to 0.075 inch, so a worn or undersized #1 bit will cam out. Keep a spare 2R bit on the driver for a 100-count jar.

The JTSS9SS is a Type A tapping screw with a gimlet point, which is the sharp spaced-thread point made for thin sheet metal and soft materials. It will start in a punched or drilled clearance hole in thin stock, but it is not a self-drilling screw, so there is no drill flute on the tip. For thicker gauge steel, drill a pilot first. The thread count is 15 threads per inch to the ASME B18.6.4 thread standard.

Mechanically yes, but be aware of the corrosion risk. Metallics notes that fastening stainless steel parts to aluminum or steel can create a galvanic couple in some environments, which corrodes the softer base metal. Indoors and dry, that is usually a non-issue. Outdoors, in wet locations, or on coastal jobs, either isolate the joint or use a fastener that matches the base metal.

No. The JTSS9SS is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, these will not satisfy it and you need a domestically produced fastener instead.

Minimum torsional strength is 39 lb-in. That is low compared with hardened carbon steel screws, which is normal for 18-8 stainless, so run them with a clutch or low-torque setting rather than an impact driver. In 18-8 the screw will twist off before it strips the hole in thicker material.

They ship in a jar of 100, and 100 is the order minimum. The jar weighs 0.6 lbs. Other sizes and quantities are available by request.

Metallics lists them for the electrical, plumbing, heating and air conditioning industries. Typical use is mounting devices, straps, plates, and light sheet metal work where the stainless material matters, such as damp locations or wash-down areas. The square drive is the practical advantage overhead, since a 2R bit holds the screw without a second hand.

Head dimensions are to ASME B18.6.3-2013 and threads are to ASME B18.6.4. One caveat worth knowing if you are checking against a spec sheet: dimensions for the #9 diameter are independent of ASME B18.6.4.