Metallics JTSS83V 12 x 3 in. Pan Head Square Drive Tapping Screws - Steel Zinc - Each

A #3 square (Robertson) bit. The JTSS83V uses a square recess sized 3R, with the recess measuring 0.133 inch across the flats and a gaging depth of 0.080 to 0.095 inch. Keep a couple of spare #3 bits on the truck if you're driving a full jar of 500.

The JTSS83V is a Type A tapping screw with a gimlet point, so it starts and forms its own thread in sheet metal and soft materials without a pilot hole in most cases. In harder or thicker stock, a pilot hole keeps you from snapping the screw; torsional strength is rated at 83 lb-in minimum, so drive it with a clutch rather than an impact at full power.

No. The JTSS83V is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your job carries domestic-sourcing requirements, this screw won't clear the submittal and you'll need a domestically produced fastener.

Eleven threads per inch over a 3 inch length, cut to ASME B18.6.4 thread standard. A Type A thread is coarse and widely spaced by design, which is what lets it bite in thin sheet metal and softer substrates. With 3 inches of shank you can go through furring, strapping, or a stack of light-gauge material and still land threads in the base.

These are carbon steel with a zinc plating, which is a general-purpose indoor and protected-location finish. Zinc plate resists incidental moisture but it isn't a marine or sustained-exposure coating. For wet locations, exterior runs, or anything near chemicals, go to a hot-dip galvanized or stainless fastener instead.

Head and recess dimensions follow ASME B18.6.3-2013, threads follow ASME B18.6.4, and the steel is AISI 1016 to 1024 case hardened to Rockwell C28-38. That combination is what a spec writer or inspector is looking for when a submittal calls for a standard Type A tapping screw rather than a proprietary fastener.

They ship in a jar of 500 pieces, and 500 each is the order minimum. There is no smaller count on the JTSS83V, so it's a stocking quantity for a crew or an MRO shelf rather than a handful for one device.

A Type A screw like the JTSS83V has a gimlet point: it pierces and taps thin sheet and soft material, but it has no drill flute, so it won't cut its own hole in heavier steel. If you're fastening into structural or thicker gauge metal, a self-drilling screw with a drill point is the right call. For sheet metal, electrical enclosures, strapping, and soft substrates, the Type A point drives faster and with less cam-out.

The square recess on the JTSS83V has slightly tapered side walls and a conical bottom, which lets a #3 square bit hold the screw on the bit without a finger behind it. That matters on a 3 inch screw driven overhead or in a panel. It also resists cam-out better than a Phillips when you are pushing toward the 83 lb-in torsional limit.