Value Collection 451208BR Hex Head Cap Screw 5/8-18x14 Gr8

Product Description

The VALUE COLLECTION 451208BR is a Grade 8 steel hex head cap screw with a 5/8-18 UNF thread and a 14-inch length under head. This is a partially threaded fastener, meaning the shank runs unthreaded for a portion of its length before the thread begins — a design suited for applications that require a bearing surface or clamping without thread engagement through the full grip length. The bright, uncoated finish leaves the steel in its natural state without plating or coating. It meets ASME B18.2.1 dimensional standards and is driven with a 15/16-inch hex key or wrench. Machinists, millwrights, and maintenance technicians are the typical installers.

This fastener is used in heavy industrial, structural, and mechanical assembly applications where high tensile strength is required. Grade 8 fasteners are specified in applications involving high clamping loads, vibration-prone assemblies, or joints where a lower-grade fastener would be underrated. The 14-inch length makes this screw appropriate for thick-section connections, long-reach clamping setups, or through-bolting applications in fabricated steel frames and machinery bases. It is sold individually and sized in the inch measurement system.

Key Features

• Grade 8 steel construction for high tensile and proof load capacity
• 5/8-18 UNF thread form provides finer thread pitch for precise clamping and better vibration resistance than coarse thread equivalents
• 14-inch length under head accommodates thick-section or long-reach bolting applications
• Partially threaded shank provides an unthreaded bearing surface along part of the grip length
• Bright uncoated finish — no plating that could affect dimensional tolerance in precision fits
• Conforms to ASME B18.2.1 for dimensional consistency

Compatibility

Designed as an OEM-style or maintenance replacement hex head cap screw for industrial and mechanical assemblies requiring a 5/8-18 UNF partially threaded fastener in Grade 8 steel per ASME B18.2.1.

Installation Notes

Installation is typically performed by millwrights, maintenance technicians, or machinists using a standard 15/16-inch open-end, box-end, or socket wrench. Always confirm the mating thread is also 5/8-18 UNF before installation, as mixing UNF and UNC threads in the same joint will damage both the fastener and the tapped hole. Torque to the value specified in the engineering documentation for the joint — do not estimate torque for Grade 8 fasteners without a reference. Follow all applicable industry and facility safety standards when working in structural or pressure-bearing assemblies.