Metallics JFM79 6-32 x 1-3/4 in. Flat Head Slotted Machine Screws - Steel Zinc - Each

6-32 is the standard thread used for device mounting in outlet and switch boxes, and the Metallics JFM79 is a 6-32 UNC screw cut to the ANSI/ASME B1.1 thread standard at 32 threads per inch, so it mates with 6-32 tapped holes in boxes, plaster rings, and device yokes. At 1-3/4 inches long it is intended for deep builds, thick plaster rings, or stacked spacers rather than flush device mounting.

Yes, flat head means the screw seats flush with the surface, which requires a countersunk or chamfered hole. The head measures 0.238 to 0.262 inch across with a head height of 0.069 to 0.083 inch, so the countersink has to be cut for roughly a quarter-inch head. If the mounting hole is a plain drilled hole with no countersink, a round or pan head screw is the better choice because a flat head will stand proud and rock.

These are zinc plated steel, made from AISI 1006 to 1022 low carbon steel. Zinc plating is a dry-location and indoor-equipment finish; it gives light corrosion protection but will eventually bloom and rust in wet, outdoor, or washdown areas. For exterior enclosures, coastal sites, or anywhere subject to moisture, specify a stainless machine screw of the same 6-32 x 1-3/4 size instead.

No. The JFM79 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this screw will not satisfy it and you need a domestically produced fastener.

The JFM79 ships as a jar of 100 screws, and 100 is the order minimum. Buying by the jar is how MRO and electrical stockrooms keep a common size on the shelf rather than pulling singles off a job.

550 pounds minimum tensile, with a hardness of Rockwell B70 to B100. That is ample for mounting devices, covers, plates, small brackets, and control components, which is what a 6-32 is used for. It is not a structural fastener, and in thin sheet metal the limiting factor is almost always the threads in the base material, not the screw.

Head, slot, and body dimensions conform to ASME B18.6.3-1998, and the threads follow ANSI/ASME B1.1. Those two references are what a spec reviewer looks for when a submittal calls out a standard machine screw rather than a proprietary fastener.