Metallics DS184B 10 x 1-1/2 in. 5/16 Indented Hex Head Slotted Sharp Point Tapping Screws - Steel Zinc - Each

The DS184B is a Type A tapping screw, the sharp gimlet-point style made for thin sheet metal: it pierces and forms its own thread in sheet steel, duct, and box flanges without a pilot tap. Metallics lists it for the electrical, plumbing, heating and air conditioning trades. For thicker material or structural steel, a thread-cutting or self-drilling screw is the right call instead, since a gimlet point relies on thin stock to form a thread.

No. Country of origin on the DS184B is multiple, and Metallics reports its ARRA and Buy American status as undetermined, so it should not be submitted as domestic material on a federally funded job. For those specs you need a fastener with a documented domestic origin.

Yes, it's a hex washer head. The washer section runs 0.384 to 0.414 inch outside diameter and 0.019 to 0.031 inch thick, which spreads the clamp load over sheet metal and oversized holes, and head height is 0.105 to 0.12 inch. Dimensions follow ASME B18.6.3-2010.

It's a #10 diameter by 1-1/2 inch screw with 12 threads per inch, threaded to ASME B18.6.4 as a Type A sharp point. Because it's a gimlet point Type A, it is meant to be started in a pierced or punched hole in thin sheet rather than a tapped hole, so match the pilot to the screw's root diameter in the gauge of metal you're fastening.

The screws are case hardened to Rockwell C28-38 with a minimum torsional strength of 48 lb-in, made from AISI 1016-1024 steel. That is enough to drive and form threads in sheet metal, but 48 lb-in is the floor for twist-off, so keep impact torque moderate and stop at seating rather than over-driving.

The DS184B is steel with a zinc finish. Zinc plating handles indoor and protected work, dry duct runs, panel and box fastening. For sustained exterior exposure, wet locations, or anywhere near chemicals or coastal air, specify a stainless tapping screw instead, since plated carbon steel will eventually corrode once the plating is scratched by driving.

They ship as a box of 3,000, which is the order minimum for the DS184B. Box weight is listed at 29.4 lbs. If you need a smaller count or a different length in the same indented hex slotted Type A, Metallics offers other sizes and quantities by request.

No, and the difference matters on the job. The DS184B is a Type A sharp gimlet point screw: it needs a punched or pre-pierced hole and forms its thread as it goes. A self-drilling screw carries a drill tip that makes its own hole in heavier gauge steel. If you're fastening into material too thick to pierce with a sharp point, order a self-drilling screw rather than this one.