Value Collection D39039 Hex Head Cap Screw 5/16-18 Grade 8

Product Description

The VALUE COLLECTION D39039 is a partially threaded hex head cap screw designed for high-strength fastening applications in mechanical, industrial, and construction assemblies. Manufactured from Grade 8 steel with a zinc yellow dichromate finish, this fastener delivers superior tensile strength and corrosion resistance compared to lower-grade alternatives. The 5/16-18 UNC thread profile and 3.5-inch length under head make it well suited for through-bolt and clamped-joint configurations where vibration resistance and load-bearing integrity are required. Installation follows ASME B18.2.1 standards, ensuring dimensional consistency for precision assemblies.

This cap screw is used in a wide range of industrial and trade applications including equipment mounting, structural steel fabrication, machinery assembly, and general maintenance repair. The partial threading allows a smooth shank section to carry shear loads more effectively than fully threaded fasteners of the same length, making it a preferred choice in bolted joints subject to lateral forces. It is commonly installed by millwrights, maintenance mechanics, pipefitters, and general contractors.

Key Features

• Grade 8 steel construction provides high tensile and proof load strength for demanding fastening applications
• Zinc yellow dichromate finish offers corrosion resistance and provides visual identification as a Grade 8 fastener
• Partially threaded shank carries shear loads more effectively than fully threaded designs
• 5/16-18 UNC thread standard ensures broad compatibility with standard inch-series nuts and tapped holes
• Meets ASME B18.2.1 dimensional standards for consistent fit in precision assemblies

Compatibility

Designed for use with standard 5/16-18 UNC inch-series hex nuts, flat washers, and tapped holes conforming to Unified National Coarse thread specifications per ASME B18.2.1.

Installation Notes

Installation should be performed by a qualified mechanic or tradesperson using an appropriate hex wrench or socket driver sized for a 5/16-inch hex head fastener. Always verify that mating threads and tapped holes are clean and free of debris before installation. Do not exceed the rated proof load of the fastener, and use calibrated torque tools where joint specifications require controlled preload. Grade 8 fasteners should not be substituted with lower-grade hardware in structural or load-bearing joints.