Holo-krome 60066 Flat Socket Cap Screw 1/4-20 X 1-1/4 in

Product Description

The HOLO-KROME 60066 is a flat socket cap screw designed for flush or countersunk fastening applications in mechanical assemblies, tooling, and machine construction. It features an 82-degree flat head with a 5/32-inch hex socket drive and is fully threaded along its 1-1/4-inch overall length. The 1/4-20 UNC thread profile is manufactured to a 3A thread fit class, providing a close tolerance engagement suitable for precision assemblies. Base material is alloy steel finished in black oxide for moderate corrosion resistance and reduced light reflection. Hardness is rated at 39-44 HRC, meeting ASME B18.3 and ASTM F835 standards. This screw is installed by machinists, millwrights, and maintenance technicians using a 5/32-inch hex key.

This screw is suited for applications where the fastener head must sit flush with or below the surface of the mating material, including fixtures, jigs, machine frames, and precision equipment. The 82-degree flat head profile is the standard angle for countersunk holes in inch-dimensioned metalwork. The black oxide finish makes it a common choice in industrial and tooling environments where a low-profile, non-reflective fastener is required. It is sold individually with a minimum order quantity of 100 pieces.

Key Features

• 82-degree flat head seats flush in standard inch countersunk holes
• 5/32-inch hex socket drive for precise torque application
• Fully threaded 1/4-20 UNC, 3A thread fit class for tight tolerance engagement
• Alloy steel construction rated 39-44 HRC for high tensile strength
• Black oxide finish provides mild corrosion resistance and low-glare appearance
• Meets ASME B18.3 and ASTM F835 fastener standards

Compatibility

Designed as a standard inch-series flat socket cap screw compatible with countersunk holes dimensioned for an 82-degree included angle and 1/4-20 UNC threaded bores in metal assemblies per ASME B18.3.

Installation Notes

Installation is performed by machinists or maintenance technicians using a 5/32-inch hex key or Allen driver. The mating countersunk hole should be dimensioned to the 82-degree flat head profile per ASME B18.3 to ensure proper head seating. De-energize and lock out any equipment before fastener replacement or removal. Avoid over-torquing, as alloy steel screws at this diameter can be damaged if drive engagement is incomplete or the countersink is undersized.