Value Collection -40879-2 Button Socket Cap Screw 5/16-18

Product Description

The VALUE COLLECTION -40879-2 is a button socket cap screw designed for mechanical assemblies requiring a low-profile fastener with high torsional strength. Sized at 5/16-18 with a 3/4-inch length under the head, this fully threaded fastener is manufactured from alloy steel and finished with a black oxide coating for corrosion resistance and reduced light reflection. The 3/16-inch hex socket drive accepts a standard hex key. Hardness is rated at 36-43 HRC, meeting the demands of high-load fastening applications. Machinists, millwrights, and mechanical contractors use this screw where a standard hex cap would protrude too far from the mating surface.

This button socket cap screw suits general industrial and mechanical applications where a flush or near-flush head profile is required. Typical use cases include machine guards, fixtures, enclosures, and equipment panels. The UNC thread form and Class 3A thread fit provide a controlled tolerance for consistent engagement. Conformance to ANSI/ASME B18.3 and ASTM F835 makes it appropriate for applications where fastener standards are specified by design documentation or inspection requirements.

Key Features

• Button head profile keeps fastener height low in the assembly
• Alloy steel construction with 36-43 HRC hardness for high-load service
• Black oxide finish provides mild corrosion resistance and matte appearance
• 3/16-inch hex socket drive for standard hex key installation
• Fully threaded 5/16-18 UNC, Class 3A thread fit for consistent engagement
• Meets ANSI/ASME B18.3 and ASTM F835 standards

Compatibility

Designed as a standard replacement or stocking fastener for any mechanical assembly specifying a 5/16-18 UNC button socket cap screw per ANSI/ASME B18.3 or ASTM F835.

Installation Notes

Installation requires a 3/16-inch hex key or hex bit driver. Confirm mating thread condition and ensure the hole is free of debris before driving. Do not exceed the rated torque for the 5/16-18 thread size per applicable fastener standards. Alloy steel with black oxide finish is not a substitute for stainless or plated hardware in wet or corrosive outdoor environments.