Metallics DS152B 8 x 1/2 in. 1/4 Indented Hex Head Slotted Sharp Point Tapping Screws - Steel Zinc - Each

The DS152B is a Type A tapping screw with a gimlet (sharp) point, so it drills its own thread as it drives into thin sheet metal without a tapped hole. Thread count is 15 per inch to ASME B18.6.4. Metallics lists it for electrical, plumbing, heating and air conditioning work as well as concrete and masonry applications (in masonry it goes into an anchor or plug, not the solid material).

Metallics lists the DS152B as both ARRA compliant and Buy American compliant. Country of origin is recorded as multiple, so if your contract requires a single documented origin, request the certification for the specific lot shipped.

Two options. The head is an indented hex measuring 0.244 to 0.25 in. across the flats and 0.272 in. across the corners, so a 1/4 in. hex driver or nut setter seats on it. It is also slotted, with a slot 0.045 to 0.054 in. wide and 0.052 to 0.066 in. deep, so a flat blade screwdriver works where a driver cannot reach. Head height runs 0.096 to 0.11 in.

Driven correctly, yes. The screw is heat treated to Rockwell C28-38 from AISI 1016-1024 steel and carries a minimum torsional strength of 39 lb-in, which is the point at which the shank would twist off. At 1/2 in. long it is sized for sheet metal thicknesses where the full thread engages the panel, not for deep stack-ups.

The DS152B is steel with a zinc plated finish, which is a general purpose coating for dry indoor and protected work, panels, boxes, strut and interior duct. It is not a coastal or continuously wet duty finish. For exterior or wash-down locations, specify a stainless or hot dip galvanized fastener instead.

Dimensions follow ASME B18.6.3-2010 and the thread form follows ASME B18.6.4. Steel is AISI 1016-1024. One caveat from the manufacturer: dimensions for the #9 diameter in this family are independent of ASME B18.6.4, so if you are submitting on a #9 rather than this #8, note that on the submittal.

The DS152B ships as a box with an order minimum of 10,000 pieces. Box weight is listed at 37 lbs. If you need a smaller count or a different length in the same indented hex slotted pattern, Metallics states other sizes and quantities are available by request.

A Type A screw, which is what the DS152B is, has a widely spaced coarse thread (15 per inch here) and a sharp gimlet point for driving into a pre-punched or pilot hole in thin sheet metal. A Type AB has a finer thread on the same sharp point and suits a broader range of materials. A self-drilling screw carries a drill tip and needs no pilot hole at all. Choose Type A where the hole is already punched, as in enclosures, boxes and light gauge brackets.

Yes, the head carries a washer section 0.322 to 0.348 in. outside diameter and 0.019 to 0.031 in. thick. That larger footprint spreads load over the hole, which matters when you are fastening through thin gauge metal or a slotted bracket where a plain hex head would pull through.

Order Metallics part DS152B, from the JDS series: a #8 x 1/2 in. indented hex head slotted sharp point tapping screw in zinc plated steel with a 1/4 in. hex head.