Metallics JTSF22 8 x 1-1/4 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

The Metallics JTSF22 is a Type A tapping screw, which means it cuts its own thread as it drives and is intended for thin sheet material rather than pre-tapped holes. It has a gimlet point, so it starts in a pilot hole in sheet metal and forms the thread on the way in. Metallics lists it for the electrical, plumbing, and heating and air conditioning trades, so typical work is hanging boxes, straps, duct, and brackets to sheet metal.

No. The JTSF22 is not Buy American compliant and is not ARRA compliant; country of origin is listed as multiple. For federally funded work carrying domestic-sourcing requirements you will need a domestically produced fastener instead.

A #2 Phillips bit. The recess is 0.182 in. in diameter, 0.11 in. deep, and 0.03 in. wide at the wings, which is standard #2 geometry, so a worn or undersized bit will cam out and chew the recess.

15 threads per inch on a #8 diameter, which is the coarse Type A pitch for sheet metal. Thread form follows ASME B18.6.4. Coarse pitch is what you want biting thin gauge stock; it is not a machine screw and will not run into a tapped #8-32 hole.

The JTSF22 is steel with a zinc finish, which is a dry-location and indoor-protected plating. Zinc plated carbon steel will corrode in continuous moisture, exterior exposure, or chemical environments, so for outdoor or washdown work specify a stainless fastener instead.

Case hardened to Rockwell C28-38 with a 39 lb-in minimum torsional strength, made from AISI 1016 to 1024 carbon steel. That rating is the drive torque the screw body will take before twisting off, so keep an impact driver's clutch down and stop once the head seats. Over-torquing a Type A screw in heavier gauge is the usual cause of a snapped shank.

Dimensions conform to ASME B18.6.4-1998 and the thread to ASME B18.6.4. Gaging diameter is 0.267 with protrusion 0.023 to 0.039 above the gage, which is the B18.6.4 recess-penetration check. Note that Metallics states dimensions for #9 diameter screws are independent of ASME B18.6.4, but the #8 JTSF22 is covered by it.

The JTSF22 is a #8 diameter at 1-1/4 in. length, which gives you roughly an inch of thread engagement past a thin bracket or strap. For sheet metal to sheet metal it is more length than needed; its use is fastening through a thicker member such as a box ear, wood blocking, or a spacer into sheet steel. Other lengths in the JTSF series are available by request.

They ship in a jar of 100, and the jar is the order minimum, so 100 pieces is the smallest quantity. The filled jar weighs 0.59 lbs. Metallics lists other sizes and quantities as available by request.