Metallics JRM52SLT 12-24 x 1-1/2 in. Round Head Slotted Machine Screws - Steel Zinc - Each

The round head measures 0.382 to 0.408 inch across and stands 0.139 to 0.153 inch above the surface. That domed profile sits proud rather than flush, so if you need the fastener flush with a plate or panel, a flat head countersunk screw is the right choice instead.

The JRM52SLT carries a 60,000 psi minimum tensile strength with a Rockwell B70-B100 hardness, made from AISI 1006-1022 low carbon steel. That is standard commercial machine screw material, fine for device mounting, brackets and enclosures. It is not a graded structural bolt, so for load-bearing connections you want a graded hex cap screw rather than a machine screw.

Zinc plated steel is a dry to normally dry indoor finish. It gives light corrosion resistance for interior boxes, panels and enclosures, but in wet, exterior or washdown locations the plating will eventually rust through. For those openings use a stainless machine screw of the same 12-24 x 1-1/2 size.

They ship in a jar of 100 count, and 100 is the order minimum, so you are buying by the jar rather than by the piece. Jar weight is listed at 1.5 lbs.

The JRM52SLT is flagged Buy American compliant and ARRA compliant in the manufacturer data, though country of origin is listed as China. On a federally funded project, verify which compliance clause your spec actually invokes, since the origin and the compliance flags are not the same test.

A machine screw has a uniform 12-24 machine thread and needs a tapped hole or a nut, which is exactly what an electrical box or device bracket gives you. A sheet metal screw forms its own thread in unthreaded material. If the hole you are driving into is already tapped, the JRM52SLT is the correct screw; if you are piercing bare sheet, it is not.