Value Collection 011221PR Hex Socket Cap Screw 5/16-18 Unc

Product Description

The VALUE COLLECTION 011221PR is a 5/16-18 UNC hex socket cap screw designed for secure, high-torque fastening in mechanical, structural, and industrial assemblies. Measuring 3-1/4 inches in length under head, this partially threaded fastener is driven with a 1/4 inch hex key. The alloy steel construction provides high tensile strength, while the black oxide coating offers mild corrosion resistance and a low-reflectance surface finish. It meets ASME/ANSI B18.3 and ASTM A574 standards, making it appropriate for applications where rated mechanical fasteners are specified. Machinists, millwrights, equipment technicians, and general contractors commonly use this type of socket head cap screw in precision assemblies and machinery mounting.

This fastener is suited for use in machine frames, fixture plates, jigs, tooling, and structural assemblies where a recessed drive head is preferred over an external hex or slotted style. The partial threading allows the unthreaded shank to act as a shoulder in clearance holes, providing accurate alignment and shear resistance. It is appropriate for both light industrial and heavy-duty mechanical applications where high clamping force is required in tight or recessed spaces.

Key Features

• 5/16-18 UNC thread size for standard inch-series tapped holes
• 3-1/4 inch length under head with partial threading for shank-fit clearance applications
• 1/4 inch hex drive socket head for use with standard hex keys or Allen drivers
• Alloy steel construction rated to ASTM A574 for high tensile and proof load strength
• Black oxide finish for mild corrosion resistance and reduced surface glare
• Conforms to ASME/ANSI B18.3 dimensional standards

Compatibility

Designed as a standard ASME/ANSI B18.3 socket head cap screw for use in any 5/16-18 UNC tapped hole requiring a partially threaded, hex-drive fastener.

Installation Notes

Installation is performed with a 1/4 inch hex key or Allen-style driver. Ensure the mating tapped hole is clean and properly formed to 5/16-18 UNC specification before driving. Apply thread-locking compound or hardened washers as required by the assembly specification. Do not exceed the torque rating of the mating material, and never use an impact driver without a rated hex bit socket adapter.