Metallics JRM120 10-32 x 3-1/2 in. Round Head Combo Machine Screws - Steel Zinc - Each

Yes. The Metallics JRM120 is a 10-32 machine screw, 32 threads per inch, which is the standard thread used for device mounting and outlet box screw holes in North American electrical work. At 3-1/2 inches long it is meant for deep-set boxes, thick plaster rings, or stacked mud rings where a standard 1-inch device screw runs out of reach.

Metallics lists the JRM120 as ARRA compliant and Buy American compliant, with China given as country of origin. On a federally funded job, verify which program and clause your spec invokes, since the compliance flags and the origin point in different directions.

For a normal device in a flush box, yes, that is far more length than you need. The JRM120 at 3-1/2 inches is for deep conditions: ganged mud rings, thick tile or stone finishes, fixture canopies standing off a box, or shimming a device forward. If your finish depth is under an inch, order a shorter 10-32 so you are not bottoming threads or cutting screws on site.

It is a combo head, slotted and Phillips in the same recess, so either a flat blade or a #2 Phillips works. Metallics specifies a #2 driver size. Slot width runs 0.05 to 0.06 in. and slot depth 0.065 to 0.087 in., so a standard cabinet-tip flat blade seats fine. The Phillips recess is 0.182 to 0.195 in. across.

The round head measures 0.334 to 0.359 in. across with a head height of 0.123 to 0.137 in., so it stands roughly an eighth of an inch proud of the surface. A round head is not flush-seating. If you need the head buried in a countersunk hole or sitting flat under a plate, use a flat head or oval head machine screw instead.

They ship in a jar of 100, which is the order minimum (100 count). Jar packaging suits a van stock or shop bin rather than a single-fixture repair. Total packed weight is 2.43 lbs.

Zinc plating on carbon steel is a mild corrosion coating meant for dry interior service. The JRM120 is steel with a zinc finish, made from AISI 1006 to 1022 low carbon steel. For wet locations, exterior boxes, or coastal exposure, specify a stainless 10-32 machine screw instead; the zinc will eventually rust through in standing moisture.

Minimum tensile strength is 60,000 psi with a hardness of Rockwell B70 to B100, which is typical low carbon steel machine screw territory. They hold fine in tapped sheet steel boxes and device straps, but they are not a structural or Grade 5 fastener, so do not use them where a shear or load rating is called out on the drawing.