Metallics JDSP179 14 x 2 in. 3/8 Hex Head Phillips Sharp Point Tapping Screws - Steel Zinc - Each

Two choices on the JDSP179. The head is a 3/8 inch hex, so a 3/8 nut driver or socket works, and the head is also Phillips drilled for a #3 Phillips bit. On overhead or ladder work most crews run the 3/8 socket since it holds the screw without cam-out.

The JDSP179 is a Type A tapping screw with a gimlet (sharp) point, which is the point made for starting in thin sheet metal, and it runs 10 threads per inch. In light gauge sheet it starts without a pilot. In heavier stock or in steel studs you still want a pilot hole, since Type A relies on the material being thin enough for the sharp point to form its own thread.

Metallics lists the JDSP179 as both ARRA compliant and Buy American compliant. Country of origin is China, so if your spec demands domestic melt and manufacture rather than Buy American program compliance, confirm which standard the contract is written to.

The JDSP179 ships as a jar of 100 count, and 100 is the order minimum. Metallics notes other sizes and quantities are available by request.

Steel to AISI 1016-1024, dimensionally to ASME B18.6.3-2013 with threads to ASME B18.6.4, case hardness Rockwell C28-38, and 125 lb-in minimum torsional strength. That is the spec sheet an inspector or a submittal package usually asks for on a Type A tapping screw.

The JDSP179 is zinc plated steel. Zinc plating handles indoor and dry or occasionally damp conditions, not sustained exterior exposure, wet locations, or coastal air. For those, step up to a stainless or hot dip galvanized fastener instead.

The JDSP179 has a 2 inch shank length under the head, so your combined fastened thickness plus the thread engagement in the base material has to fit inside that 2 inches. For strut, box, or hanger attachment into light steel, allow at least 3 to 4 threads of engagement past the back side of the base metal.

Type A, like the Metallics JDSP179, has a coarse 10 TPI thread and a sharp gimlet point for thin sheet metal. It does not drill its own hole in heavier steel. If you are fastening into structural steel, deck, or anything over light gauge, use a self-drilling screw with a drill point instead and keep Type A for sheet metal enclosures, duct, and light hangers.

Metallics lists the packed jar at 2.45 lbs, 3.5 in by 3.5 in by 5.75 in. Useful when you are counting van stock space or figuring freight on a multi-jar order.