Metallics JSTSP31 14 x 2 in. Pan Head Phillips Tapping Screws - 18-8 Stainless - Each

The Metallics JSTSP31 is a Type A tapping screw with a gimlet point, meaning it has a sharp tapered tip and widely spaced threads that cut their own thread as they drive into thin sheet metal or a pilot hole. Type A is the sheet metal screw thread form, not a machine screw thread, so it does not mate with a nut or a tapped machine thread. At 10 threads per inch, it is coarse-threaded and also bites well into wood and soft materials. Use a machine screw instead if you need to thread into a nut, insert, or tapped hole.

You can, but watch the environment. Fastening 18-8 stainless parts to aluminum or steel can set up a galvanic couple, a form of corrosion that attacks the less noble metal, in some conditions. Outdoors, in wet, coastal, or chemically exposed locations, that matters more than in a dry interior. The 18-8 stainless itself gives good general corrosion resistance, which is why these are specified where plated carbon steel would rust out.

The JSTSP31 is rated at a 125 lb-in minimum torsional strength. That is the floor for twisting the fastener off, and it is the number to watch if you are driving with an impact driver into steel, since stainless work-hardens and galls more readily than plated carbon steel. Drive at moderate speed, and in heavier gauge material drill a pilot hole rather than letting the gimlet point fight its way through.

Yes. The JSTSP31 pan head is built to ASME B18.6.3-2013 for head dimensions, and the thread form follows ASME B18.6.4, the tapping screw standard. Both are citable on a submittal. One caveat from the manufacturer: dimensions for the #9 diameter in this series fall outside ASME B18.6.4, so if you are standardizing a facility on this series, specify the diameters you need rather than assuming every size in the family is covered.

Metallics lists the JSTSP31 as ARRA compliant and Buy American compliant, with China as the country of origin. If your project carries a domestic sourcing clause, use those two compliance designations on your submittal and confirm the clause your specification actually invokes, since federal programs apply different domestic content tests.

The JSTSP31 runs 2 in. in length under the pan head, so the full 2 in. is available for penetration. Type A threads need a few threads engaged past the back face of the material to hold, so figure your total stack thickness and leave at least a quarter inch of thread in the receiving material. For thin sheet metal over an air gap, 2 in. is more screw than the joint needs and the excess tip will protrude, so a shorter length in the same series is the better call.

They come in a jar of 100, and 100 count is the order minimum. The packed jar weighs 2.4 lbs. For an MRO crib or a van stock, the jar keeps them contained better than a poly bag. Other sizes and quantities in the series are available by request.