Gibraltar 831408-G Shoulder Screw 3/8 in Black Oxide Steel

Product Description

The GIBRALTAR 831408-G is a steel shoulder screw with a black oxide finish, designed for precision fastening applications where a controlled shoulder diameter and length are required. The shoulder measures 3/8 inches in diameter and 7/8 inches in length, providing an accurate bearing or pivot surface for mating components. Thread size is 5/16-18 UNC, driven by a 3/16-inch hex socket. The head stands 1/4 inch tall with a 9/16-inch diameter. Built from grade 1137 steel, this screw suits machine shops, tool-and-die, fixture building, and general mechanical assembly work where dimensional precision matters.

Shoulder screws like the 831408-G are commonly used in industrial and mechanical applications requiring a smooth, precise shaft for bearings, bushings, linkages, or stripper bolts in die sets. They are installed in settings ranging from light manufacturing fixtures to equipment jigs and tooling. Trade professionals and machinists typically specify this type of fastener wherever a rotating or sliding interface is needed at a fixed location.

Key Features

• 3/8-inch shoulder diameter with 0.3750-inch decimal precision for accurate bearing fits
• 7/8-inch shoulder length provides controlled engagement depth for mating parts
• 5/16-18 UNC thread for secure fastening into tapped holes
• Black oxide finish for mild corrosion resistance and reduced light reflection
• Grade 1137 steel construction for adequate strength in general mechanical applications
• 3/16-inch hex socket drive for installation with standard Allen keys or hex drivers

Compatibility

Designed as an OEM-style replacement or standard-spec shoulder screw for mechanical fixtures, tooling assemblies, and precision fastening applications requiring a 3/8-inch shoulder diameter and 5/16-18 UNC thread.

Installation Notes

Installation is typically performed by machinists or maintenance technicians using a 3/16-inch hex key or socket driver. Ensure the tapped receiving hole meets 5/16-18 UNC thread specifications before installation. Do not overtighten, as the shoulder shoulder-to-hole clearance must be maintained for proper bearing or pivot function. Verify shoulder length is appropriate for the total stack height of mating components before final assembly.