Holo-krome 60018 Flat Socket Cap Screw 5-40 X 5/8 in Alloy Steel

Product Description

The HOLO-KROME 60018 is a flat socket cap screw engineered for precision fastening applications where a flush or countersunk installation is required. It features an 82-degree flat head with a 5/64-inch hex socket drive, allowing installation with a standard hex key in tight clearance areas. Manufactured from alloy steel with a black oxide finish, it carries a hardness rating of 39-44 HRC, making it suitable for high-strength clamping and mechanical assembly work. The screw is fully threaded along its 5/8-inch overall length and conforms to ASME B18.3 and ASTM F835 standards. Machinists, tool-and-die technicians, and maintenance mechanics are the primary installers.

This screw is intended for use in machine tool fixtures, jigs, dies, and precision mechanical assemblies where a low-profile, countersunk fastener is needed. The 5-40 UNC thread designation suits fine-pitch, small-diameter applications common in instrument assemblies, electronics enclosures, and light mechanical components. The black oxide finish provides a degree of corrosion resistance and reduces light reflection in optical and precision environments. Thread fit class 3A ensures close dimensional tolerances for reliable engagement in tapped holes.

Key Features

• 82-degree flat head seats flush in standard countersunk holes
• 5/64-inch hex socket drive for installation with a standard hex key
• Alloy steel construction with 39-44 HRC hardness for high clamping strength
• Black oxide finish for mild corrosion resistance and low-reflectance appearance
• Fully threaded over the entire 5/8-inch length for maximum thread engagement
• Meets ASME B18.3 and ASTM F835 fastener standards

Compatibility

Designed as an OEM-style replacement or new-installation fastener for any application requiring a fully threaded, 5-40 UNC, 82-degree flat head socket cap screw with a 5/64-inch hex drive per ASME B18.3.

Installation Notes

Installation requires a properly sized countersink bored to 82 degrees to ensure correct head seating. Use the appropriate 5/64-inch hex key and avoid over-torquing, which can strip the small-diameter thread or crack the head seat. Always ensure the mating tapped hole conforms to a 3A thread fit class for proper engagement. De-energize or lock out any equipment before replacing fasteners in live machinery per applicable safety procedures.