Value Collection 581390PR Hex Socket Cap Screw 1/4-20 Unc

Product Description

The VALUE COLLECTION 581390PR is a hex socket cap screw designed for high-strength fastening in mechanical assemblies, tooling fixtures, and industrial equipment. It features a 1/4-20 UNC thread with a 3/16-inch hex drive socket and measures 8 inches in length under the head. The screw is partially threaded, which provides a smooth shank section that resists shear loads and helps align mated components. Constructed from alloy steel with a black oxide coating, it offers improved corrosion resistance and reduced surface reflectivity. Machinists, millwrights, and mechanical contractors install this type of fastener when torque capacity and a clean, recessed drive profile are required.

This cap screw is suited for use in machinery frames, jigs, fixtures, and structural bolting applications where a flush or recessed fastener head is needed. The 1/4-20 UNC thread is a standard unified coarse thread widely used in North American manufacturing and fabrication. The partial threading is appropriate for applications that require a bearing shank or where thread engagement needs to be limited to a specific depth. The black oxide finish provides mild corrosion resistance and is commonly specified in shop environments where oil or grease is present.

Key Features

• 1/4-20 UNC thread for compatibility with standard unified coarse tapped holes
• 8-inch length under head suits deep-reach fastening applications
• Partially threaded shank resists shear loads and aids component alignment
• 3/16-inch hex socket drive for use with standard hex keys or socket drivers
• Alloy steel construction provides high tensile and yield strength
• Black oxide coating reduces surface corrosion and minimizes light reflection in shop environments

Compatibility

Designed as an OEM-style and aftermarket replacement hex socket cap screw for standard 1/4-20 UNC tapped assemblies meeting ASME/ANSI B18.3 and ASTM A574 specifications.

Installation Notes

Installation is performed by machinists, millwrights, or mechanical contractors using a 3/16-inch hex key or socket driver. Always ensure the receiving tapped hole is clean and free of debris before driving the fastener. Consult the assembly drawing for required thread engagement depth, particularly for partially threaded screws. Follow applicable torque specifications provided by the equipment manufacturer or relevant ASME standards.