Value Collection D39455 Hex Head Cap Screw 5/8-18 Grade 8

Product Description

The VALUE COLLECTION D39455 is a 5/8-18 hex head cap screw designed for high-strength fastening applications in mechanical, structural, and industrial 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 hardware. The screw measures 3-1/2 inches under the head and features partial threading, making it well suited for clamping applications where the unthreaded shank provides additional shear strength and precise grip length control. It conforms to ASME B18.2.1 standards for inch-series hex cap screws.

This fastener is used across a wide range of trade and industrial applications, including HVAC equipment mounting, structural steel connections, machinery assembly, and general mechanical maintenance. The 5/8-18 UNF thread pitch is a fine-thread designation, commonly specified where vibration resistance or precise torque control is required. It is installed by millwrights, maintenance mechanics, pipefitters, and general contractors working on equipment frames, flanges, and structural connections requiring Grade 8 rated hardware.

Key Features

• Grade 8 steel construction for high tensile and proof load strength
• Zinc yellow dichromate finish provides corrosion protection and is visually identifiable as Grade 8
• 5/8-18 UNF fine-thread form for vibration-resistant clamping
• Partially threaded shank supports shear loading and accurate grip length
• Conforms to ASME B18.2.1 inch-series hex cap screw standard
• 3-1/2 inches length under head accommodates moderate-depth clamping stacks

Compatibility

Designed as a standard ASME B18.2.1 inch-series hex head cap screw compatible with any 5/8-18 UNF tapped hole or nut requiring Grade 8 rated fasteners.

Installation Notes

Installation should be performed using a properly sized hex socket or open-end wrench rated for the fastener grade. Always verify that the mating nut, tapped hole, and clamped materials are rated to accept Grade 8 fastener loads before final torquing. Consult applicable mechanical or structural codes for required torque values, as these are application-specific and not defined by the fastener alone. Inspect threads for damage or contamination before installation to ensure full thread engagement.