Metallics JSRM21P 10-24 x 1/2 in. Round Head Phillips Machine Screws - 18-8 Stainless - Each

The round head measures 0.334 to 0.359 inch across and stands 0.123 to 0.137 inch above the surface. That domed profile does not sit flush, so if you need the fastener level with a cover plate or a countersunk hole, use a flat head screw instead. Round head is the right pick for mounting straps, clamps, and brackets where a raised bearing surface is fine.

No. The JSRM21P is not Buy American compliant and is not ARRA compliant; country of origin is listed as multiple. On a federally funded project with domestic-sourcing language, you will need a domestically produced fastener instead.

A machine screw like the JSRM21P has a uniform 10-24 machine thread and no cutting point, so it needs an existing tapped hole or a nut. If you are driving into unprepared sheet metal or a drilled pilot hole with no threads, use a self-tapping sheet metal screw instead. Metallics lists this one for electrical, plumbing, and HVAC work, where tapped box and strap holes are the norm.

A #2 Phillips. The recess is 0.182 to 0.195 inch in diameter and 0.093 to 0.119 inch deep, so a #2 bit seats fully; a #1 will cam out and a #3 will not bottom in the recess.

18-8 stainless is the usual choice for wet, damp, and exterior enclosures because it does not rely on a plating that can be scratched off, unlike zinc-plated steel. The JSRM21P is 18-8 throughout, at Rockwell B85-B95 hardness. In chloride-heavy coastal or pool environments, 316 stainless holds up better than 18-8.

They ship in a jar of 100, and 100 is the order minimum. If you need a different length or a bulk count, Metallics offers other sizes and quantities by request.

80,000 psi minimum. Metallics notes that tensile figures for stainless screws are approximations, since there is no single performance standard for stainless machine screws. For a load-rated fastening where a specific grade must be documented, specify a graded steel bolt rather than an 18-8 machine screw.