Metallics JFMP87 8-32 x 1-1/4 in. Flat Head Phillips Machine Screws - Steel Zinc - Each

Flat head means a countersunk seat. The head on the JFMP87 runs 0.285 to 0.312 inch across and only 0.084 to 0.1 inch high, so it needs an 82 degree countersink or a factory-dimpled hole to finish flush. Into a plain drilled hole the head will stand proud by roughly the head height. If you are fastening to flat sheet with no countersink, use a pan or round head instead.

Head and recess dimensions are held to ASME B18.6.3-1998 and the threads to ANSI/ASME B1.1, so they interchange with any other B18.6.3 8-32 flat head Phillips screw. One thing to flag for public work: these are not Buy American compliant and are not ARRA compliant, with origin listed as multiple countries. If your project carries a domestic sourcing requirement, these will not satisfy it.

A #2 Phillips. The recess on the JFMP87 measures 0.182 inch across, 0.11 inch deep, with a 0.03 inch slot width, which is the standard #2 geometry. A #1 will cam out and a #3 will not seat.

850 lb minimum tensile is the rated figure for these screws, with a case hardness of Rockwell B70 to B100. The steel is AISI 1006 to 1022 low carbon, so treat it as a general purpose fastener for mounting devices, covers, straps and brackets, not as a structural or high strength bolt.

They ship 100 to a jar, and the jar is the order minimum, so the smallest buy is 100 pieces. Jar packaging is what you want on a service van or a shop bench rather than a loose bag.

The JFMP87 is zinc plated low carbon steel, which is a dry-location finish. It handles indoor electrical, plumbing and HVAC work, which is the stated field application, but zinc plating on carbon steel will eventually corrode in wet, exterior or washdown locations. For those, specify stainless machine screws instead.

A machine screw has a uniform straight 8-32 UNC thread with no point, so it needs a pre-tapped hole or a nut. It does not cut its own thread. That is why it suits box ears, plaster rings and tapped brackets. If you are driving into bare sheet metal with only a pilot hole, you want a self-tapping or thread-cutting screw, not this one.