Metallics JFM86SS 8-32 x 1 in. Flat Head Slotted Machine Screws - 18-8 Stainless - Each

Yes, that is what the flat head is for. The Metallics JFM86SS has a flat head measuring 0.285 to 0.312 in. across with a head height of 0.084 to 0.1 in., so it seats fully into an 82 degree countersink and finishes flush with the surface. If your plate or box cover is not countersunk, a flat head will stand proud and you want a round or pan head instead.

8-32 is the standard machine screw thread on electrical outlet boxes, device yokes and plaster rings, and the JFM86SS is cut 8-32 UNC with 32 threads per inch to ANSI/ASME B1.1. At 1 in. long it gives you more reach than the short screws that ship with a device, which is useful when you are shimming a yoke out to a finished wall surface.

Head and body dimensions follow ASME B18.6.3-1998 for flat head machine screws, threads follow ANSI/ASME B1.1, and the material is to SAE standard. That is enough to spec the JFM86SS dimensionally. On the procurement side, note it is not Buy American compliant and not ARRA compliant, with country of origin listed as multiple, so it will not clear a federally funded job carrying domestic sourcing requirements.

The JFM86SS is 18-8 stainless, which is the grade used where you need general atmospheric corrosion resistance, and it is the usual pick for food processing machinery and refrigeration equipment. It also holds its strength better than plain steel as application temperature climbs. For damp mechanical rooms, exterior boxes and kitchen equipment it is the right material choice over a zinc-plated steel screw.

Slotted drive, so you need a flat blade. The slot runs 0.045 to 0.054 in. wide and 0.029 to 0.045 in. deep, which is a shallow slot by modern standards. Hand-drive these or use a low-torque setting on a driver with a properly fitted blade tip. If you are running a lot of screws with an impact or cordless driver, a Phillips or combo head machine screw will be less frustrating.

A machine screw like the JFM86SS has a straight, fully formed 8-32 UNC thread with a blunt end, so it needs an existing tapped hole or a nut to thread into. It will not cut its own thread in sheet metal or drill its own pilot. Use it for device yokes, enclosure covers, panel hardware and equipment that already has 8-32 tapped holes. If you are fastening into bare sheet metal with no tapped hole, you want a self-drilling or sheet metal screw instead.

They come in a jar of 100, and 100 is the order minimum. The packed jar weighs 0.56 lbs. Metallics also offers other sizes and quantities of this flat head slotted machine screw by request if 8-32 x 1 in. is not the size you need.