Metallics JSS32516 Screw 10-32 x 5/16 SKT Set Scr Cup S (Jar 100)

It's a 10-32 x 5/16 inch socket set screw with a cup point. The 10-32 is a #10 machine screw thread at 32 threads per inch, so it mates with a 10-32 tapped hole, and the 5/16 inch length is measured over the full body since set screws are headless.

Cup point is the right pick when you want the screw to bite. The hollowed, sharp-edged ring at the tip digs into the mating surface and resists backing out under vibration, which is why cup point is the default for securing collars and conductors in tapped lugs. If you need to clamp without marring a finished or hardened surface, a flat or nylon-tipped set screw is the better choice instead.

Socket drive, so it takes a hex key (Allen wrench), not a screwdriver. There is no external head, so the screw seats flush or below the surface of the tapped hole and nothing protrudes to catch.

Order Metallics part JSS32516. That number covers the 10-32 x 5/16 cup point socket set screw in the 100-piece jar; Metallics uses sequential numbers across the thread and length range, so a different length or thread in the same family carries a different number.

Yes, they're sold as electrical fasteners and the 10-32 thread is a common size in tapped holes on connectors, straps, and conduit fittings. A cup point is what you want for holding a conductor or a collar, since it bites in and stays put under vibration. Match the thread to the existing tapped hole before ordering - a 10-32 screw will not start in an 8-32 or 1/4-20 hole.

100 pieces, packed in a jar rather than a loose bag, which keeps a small loose fastener like a 5/16 inch set screw from scattering in a van drawer or on a service cart. It's an MRO quantity for an electrician or maintenance shop replacing lost lug and collar screws, not a one-off single.