Metallics JTSF40 12 x 3 in. Flat Head Phillips Tapping Screws - Steel Zinc - Each

It's a Type A tapping screw with a gimlet point, so it's intended for thin sheet metal and similar light materials where the screw cuts its own thread in a pilot hole. The gimlet (sharp) point also lets it start into soft materials without a full lead hole. At #12 diameter with 11 threads per inch and a 3 inch length, it's the coarse-thread end of the Type A range.

Yes, the flat head is designed to seat flush in a countersink. Plan the countersink for a head width of 0.38 to 0.412 in. and a head height of 0.112 to 0.132 in. In sheet metal, dimple or countersink the sheet to that head diameter or the head will stand proud.

The JTSF40 is flagged compliant for both Buy American and ARRA. Country of origin is listed as multiple, so if your submittal requires a single named origin, state that requirement on the order.

A #3 Phillips bit. The recess is 0.262 in. diameter, 0.144 in. deep, with a 0.035 in. slot width, so a #2 bit will sit loose and cam out when you load it. Keep a #3 in the gun for these.

The JTSF40 screws are rated to a minimum torsional strength of 83 lb-in and run Rockwell C28-38 hardness, both to the ASME B18.6.4 standard. That's adequate for powered driving, but an unclutched impact driver will exceed 83 lb-in easily once the head bottoms out. Use a clutched screwgun or back off the torque setting, and keep the #3 bit seated square.

They're carbon steel with a zinc finish, made from AISI 1016-1024 steel. Zinc plating handles indoor and protected conditions; it isn't a marine or sustained-wet coating. For exterior exposure, coastal air, or treated lumber contact, specify a stainless or hot-dip galvanized fastener instead.

They ship in a jar of 100 count, and 100 is the order minimum. The packed jar weighs 2.24 lbs. Other sizes and quantities are available by request.

Dimensions follow ASME B18.6.4-1998 and the thread conforms to ASME B18.6.4. Steel is AISI 1016-1024 with Rockwell C28-38 hardness and 83 lb-in minimum torsional strength. Gaging diameter is 0.362 in., with protrusion above the gaging ring of 0.027 to 0.045 in. One note for spec writers: dimensions for the #9 diameter in this family are independent of ASME B18.6.4.

For a box ear or a one-hole strap flat to a surface, yes, a 3 inch #12 is long. The JTSF40 is the long end of the JTSF flat head Phillips range and suits reaching through furring, blocking, or stacked material before it bites. For shallower work, order a shorter length in the same JTSF series.