Value Collection 581687PS Hex Socket Cap Screw 5/8-18 Unf

Product Description

The VALUE COLLECTION 581687PS is a partially threaded hex socket cap screw designed for high-strength fastening applications in mechanical assembly, maintenance, and fabrication work. Threaded to 5/8-18 UNF specification, this fastener measures 5.5 inches under the head and is driven with a 1/2-inch hex key. Constructed from alloy steel with a black oxide coating, it delivers solid corrosion resistance alongside the mechanical strength required for demanding industrial and equipment assembly environments. The ASME/ANSI B18.3 and ASTM A574 standards govern dimensional and strength requirements for this screw.

This cap screw is suited for use in general industrial assembly, machine building, tooling fixtures, and equipment maintenance where a fine-thread UNF engagement is required for precise torque control and resistance to loosening under vibration. The partial threading allows for shoulder-style clamping and alignment in clearance-hole applications. Machinists, millwrights, and maintenance technicians typically install this fastener using standard hex key tooling.

Key Features

• 5/8-18 UNF fine thread for tight tolerances and vibration-resistant engagement
• 5.5-inch length under head accommodates thicker material stacks
• Partial threading supports clearance-hole and shoulder-clamping installations
• Alloy steel construction meets ASTM A574 mechanical strength requirements
• Black oxide finish provides mild corrosion resistance and reduces light glare
• Driven with a 1/2-inch hex key for positive, slip-resistant torque application

Compatibility

Designed as a standard ASME/ANSI B18.3 hex socket cap screw for use in any 5/8-18 UNF tapped hole requiring a partially threaded alloy steel fastener with a 1/2-inch internal hex drive.

Installation Notes

Installation is performed with a 1/2-inch hex key or Allen driver; ensure the drive tool is fully seated to avoid cam-out and socket damage. Verify thread engagement depth in the tapped hole before applying final torque. De-energize and lock out any equipment before replacing fasteners in live assemblies. Apply a thread lubricant or anti-seize as appropriate for the base material to prevent galling during installation.