Value Collection D39459 Hex Cap Screw 5/8-18 X 5 in Grade 8

Product Description

The VALUE COLLECTION D39459 is a Grade 8 steel hex head cap screw with a 5/8-18 UNF thread and a 5-inch length under head. It features a zinc yellow dichromate finish that provides corrosion resistance in moderate-exposure environments. The screw is partially threaded and manufactured to ASME B18.2.1 dimensional standards, ensuring consistent head geometry and thread tolerances. This fastener is suited for high-strength bolted assemblies where a fine-thread pitch is required for precise clamping force and resistance to loosening under vibration. Machinists, millwrights, and maintenance technicians typically specify Grade 8 hardware in this configuration for structural and mechanical applications.

This cap screw is used in industrial machinery, heavy equipment, and structural assemblies where high tensile strength and fine thread engagement are critical. The 5/8-18 UNF designation indicates a fine-thread series, which offers greater thread engagement per inch compared to coarse-thread equivalents and is preferred when working with thin-walled materials or when precise torque control is required. The partial threading allows a smooth shank to bear shear loads in bolted joints.

Key Features

• Grade 8 steel construction for high tensile and proof load strength
• 5/8-18 UNF fine-thread series for precise torque control and vibration resistance
• Zinc yellow dichromate finish for corrosion and oxidation resistance
• Partially threaded shank to accommodate shear-loaded bolted joints
• Manufactured to ASME B18.2.1 for consistent head dimensions and tolerances
• 5-inch length under head suits deeper grip applications

Compatibility

Designed for use in standard 5/8-inch UNF bolted assemblies requiring ASME B18.2.1 compliant hex head cap screws with Grade 8 strength ratings.

Installation Notes

Installation is typically performed by machinists, millwrights, or maintenance technicians using a standard hex wrench or impact driver with the appropriate 15/16-inch socket. Always use a hardened flat washer under the head when the mating surface is softer than Grade 8 steel. Verify that the mating nut or tapped hole is rated for the Grade 8 load before assembly. Follow applicable torque specifications from the equipment manufacturer or relevant engineering standards.