Value Collection 581133PR Hex Socket Cap Screw 4-40 Unc

Product Description

The VALUE COLLECTION 581133PR is a 4-40 UNC hex socket cap screw designed for precision fastening in machine assemblies, fixtures, and close-tolerance applications. Manufactured from alloy steel with a black oxide finish, it delivers solid tensile strength and moderate corrosion resistance in indoor and controlled-environment applications. The screw measures 2 inches in length under the head and is driven with a 3/32-inch hex key. Partial threading provides clamping force over an unthreaded shank, which helps resist lateral shear loads in bolted joints. Meets ASME/ANSI B18.3 and ASTM A574 standards.

This fastener is suited for light machine assembly, electronic enclosures, jigs, fixtures, and instrument panels where a low-profile socket drive is required. The 4-40 UNC thread is a fine-pitch coarse-count thread commonly used in small mechanical and electromechanical assemblies. The black oxide coating reduces light reflection and provides mild surface protection, making it appropriate for interior applications where aesthetics and modest corrosion resistance both matter. Licensed machinists, millwrights, and assembly technicians are the typical installers.

Key Features

• 4-40 UNC thread for use in standard small-machine tapped holes
• 2-inch length under head accommodates thicker stacked assemblies
• 3/32-inch hex drive for use with standard Allen or hex key wrenches
• Alloy steel construction meets ASTM A574 mechanical requirements
• Black oxide finish provides mild corrosion resistance and low reflectivity
• Partially threaded shank improves shear load performance in bolted joints

Compatibility

Designed as a standard-geometry replacement or direct-fit fastener for any 4-40 UNC tapped hole requiring a hex socket cap screw per ASME/ANSI B18.3.

Installation Notes

Installation is typically performed by machinists or assembly technicians using a 3/32-inch hex key or Allen driver. Ensure the mating tapped hole is clean and correctly sized for 4-40 UNC engagement before installation. Do not exceed the rated drive torque for alloy steel cap screws at this diameter, and never use an impact driver on small-diameter socket screws. Apply thread-locking compound if vibration is expected in the assembly environment.