Metallics JSS321 Screw 10-32 x 1 SKT S-Scr Cup St-Blk (Jar 100)

The JSS321 is a 10-32 x 1 inch socket set screw with a cup point. The 10-32 callout means a #10 diameter machine screw thread at 32 threads per inch, so it mates with a tapped 10-32 hole or a 10-32 nut. The 1 inch figure is the screw length.

Cup point is the general purpose set screw point, and that is what the JSS321 uses. The hollowed circular edge bites into the shaft or mating part and resists loosening under vibration, which is why it is the default for collars, pulleys, and hubs. It does mar the shaft. If you need to reposition the part repeatedly without leaving a ring of damage, a flat point is the better pick; for permanent location in a drilled spot, a cone point.

Steel with a black finish. That is a dry, indoor-duty combination typical of socket set screws. It carries no corrosion resistance claim, so for wet, washdown, or exterior locations specify a stainless set screw instead of the black steel version.

They ship 100 screws to a jar, which is the standard shop pack for this item. That is a bin quantity for an electrical or MRO crib rather than a single piece buy, so expect to order in multiples of 100.

It is a socket set screw, so it drives with a hex key in the internal socket, not a screwdriver. There is no head above the surface; the screw seats flush or below in a tapped hole. Have the hex key set on the truck before you get to the panel, since one size will not cover a mixed fastener bin.

Metallics catalogues it on the electrical side of the house, and 10-32 is the thread electricians see constantly on box ears, ground screws, and strut fittings. Functionally it is a general purpose socket set screw, so it is equally at home in a machine shop drawer. Same part either way.