Value Collection 721188PR Flat Socket Cap Screw 5/16-24

Product Description

The VALUE COLLECTION 721188PR is a flat socket cap screw designed for precision fastening applications where a flush or countersunk head profile is required. Sized at 5/16-24 UNF thread by 2-1/4 inches overall length, it features an 82-degree flat head with a 3/16-inch hex socket drive. The fastener is partially threaded and manufactured from alloy steel with a black oxide finish that provides moderate corrosion resistance and a dark, low-reflectance appearance. It is installed by machinists, millwrights, and maintenance technicians working on assemblies where head protrusion is not acceptable.

This screw is suited for use in machine components, jigs, fixtures, tooling plates, and mechanical assemblies requiring a countersunk fastener with fine-thread engagement. The UNF thread form provides higher thread strength and better resistance to loosening under vibration compared to coarse-thread equivalents, making it a practical choice for precision machine work and close-tolerance assemblies in industrial and manufacturing environments.

Key Features

• 82-degree flat head seats flush in standard countersunk holes, eliminating head protrusion
• 3/16-inch hex socket drive for use with standard Allen keys or hex bit drivers
• 5/16-24 UNF fine thread for higher pullout strength and vibration resistance
• Partial threading allows for shoulder-style grip in clearance holes
• Alloy steel construction meets ASME/ANSI B18.3 and ASTM F835 fastener standards
• Black oxide finish reduces surface reflectance and provides light corrosion protection

Compatibility

Designed as a standard UNF flat socket cap screw per ASME/ANSI B18.3 and ASTM F835, compatible with any 5/16-24 threaded hole requiring an 82-degree countersunk seating surface.

Installation Notes

Install using a properly sized 3/16-inch hex key or Allen-type driver to avoid rounding the socket. Ensure the mating hole is countersunk to 82 degrees to achieve full head seating. Degrease mating surfaces and apply thread lubricant or thread-locking compound as required by the assembly specification. Torque to the value specified in the applicable engineering drawing or fastener manufacturer torque table for the material and finish combination in use.