Value Collection 721163PR Flat Socket Cap Screw 1/4-28

Product Description

The VALUE COLLECTION 721163PR is a flat socket cap screw designed for precision fastening in applications where a flush or countersunk head profile is required. It features a 1/4-28 UNF thread and measures 3-1/2 inches in overall length. The 82-degree flat head seats into standard countersunk holes, and the 5/32-inch hex socket drive accepts a standard Allen key. Constructed from alloy steel with a black oxide finish, this screw offers good strength and mild corrosion resistance. It is partially threaded, providing a smooth shank section that helps maintain positional alignment in close-tolerance assemblies. Machinists, millwrights, and general maintenance mechanics install this type of fastener in metalworking, tooling, and light-to-medium structural applications.

This flat socket cap screw is suited for use in metal fabrication, jig and fixture assembly, machine guarding, and similar applications where a low-profile head is necessary to avoid interference with mating components. The fine UNF thread pitch offers tighter thread engagement compared to coarse thread fasteners, making it a common choice in precision assemblies and applications subject to vibration. The black oxide finish reduces light reflection and provides a degree of surface protection in dry or lightly oiled environments. Minimum order quantity is 5 pieces.

Key Features

• 82-degree flat head seats flush in standard countersunk holes, eliminating head protrusion
• 5/32-inch hex socket drive for use with standard Allen or hex key tools
• 1/4-28 UNF fine thread for tighter engagement and improved resistance to loosening under vibration
• Partially threaded shank aids in alignment and reduces stress concentration at the thread runout
• Alloy steel construction provides high tensile strength suitable for demanding mechanical assemblies
• Black oxide finish reduces surface glare and offers light corrosion protection in dry service conditions

Compatibility

Designed as an OEM-style replacement or standard component for assemblies requiring a 1/4-28 UNF countersunk flat socket cap screw per ASME/ANSI B18.3 and ASTM F835 fastener standards.

Installation Notes

Installation is typically performed by machinists, maintenance mechanics, or assemblers using a calibrated 5/32-inch hex key or Allen driver. Ensure the mating countersunk hole is machined to the correct 82-degree included angle before installation to achieve proper head seating. Always torque to the value specified in the applicable assembly drawing or fastener standard — do not over-drive, as alloy socket cap screws can shear if torque exceeds material limits. Confirm thread engagement length meets design requirements before final assembly.