Holo-krome 720001491 Hex Socket Cap Screw 5/16-18 Unc

Product Description

The HOLO-KROME 720001491 is a hex socket cap screw designed for high-strength fastening in demanding mechanical and industrial applications. It features a 5/16-18 UNC thread size, a 3-3/4 inch length under head, and is partially threaded for reliable clamping force. The 1/4 inch hex drive socket accepts standard hex keys and Allen wrenches. Constructed from alloy steel with a black oxide finish, this screw delivers solid corrosion resistance and clean appearance in service environments where bare steel is not acceptable. It meets ASME B18.3 and ASTM A574 standards, confirming consistent dimensional and mechanical performance.

This screw is suited for machine assembly, fixture building, tooling, and mechanical equipment maintenance where a recessed drive fastener is preferred over a hex head. The partially threaded shank provides shear strength in bolted joint applications. Electricians, millwrights, HVAC equipment assemblers, and general tradespeople will encounter this type of fastener when working on equipment panels, motor mounts, and structural brackets. The black oxide finish makes it a common choice in applications where low-profile appearance and moderate corrosion resistance are both required.

Key Features

• 5/16-18 UNC thread for standard imperial fastener compatibility
• 3-3/4 inch length under head for deeper grip applications
• Partially threaded shank provides improved shear strength in bolted joints
• Alloy steel construction meets ASTM A574 mechanical requirements
• Black oxide finish for moderate corrosion resistance and low-glare appearance
• 1/4 inch hex drive - compatible with standard hex keys and T-handle drivers
• Conforms to ASME B18.3 dimensional standards

Compatibility

Designed as a standard ASME B18.3 hex socket cap screw for use in any 5/16-18 UNC tapped hole requiring a partially threaded fastener with a 3-3/4 inch grip length.

Installation Notes

Install using a 1/4 inch hex key or Allen driver; do not use an undersized key as it will round the socket. Confirm the tapped hole is clean and free of debris before threading. Apply thread-locking compound or fastener torque per the equipment manufacturer specification for the joint being assembled. Alloy steel socket cap screws should not be substituted with lower-grade fasteners in structural or load-bearing joints.