Holo-krome 64040 Button Socket Cap Screw 1/4-20

Product Description

The HOLO-KROME 64040 is a button socket cap screw designed for mechanical assemblies where a low-profile fastening head is required. Driven by a 5/32-inch hex socket, it threads into 1/4-20 UNC tapped holes and seats flush with or slightly above the mating surface thanks to its 0.132-inch button head height. The alloy steel construction is finished in black oxide, which provides moderate corrosion resistance and reduces light reflection in finished assemblies. The fastener is fully threaded to a 3/8-inch length under the head, conforms to ANSI/ASME B18.3 and ASTM F835, and carries a thread fit class of 3A for consistent engagement. Hardness is rated at 38 HRC. Installers across mechanical, industrial, and light structural applications use this screw where clearance above the fastener head is limited.

This screw is suited for use in machine frames, equipment panels, fixtures, and assemblies that require a secure, low-profile cap fastener. The 1/4-20 UNC thread is one of the most common inch-series thread sizes in North American mechanical work, making this fastener applicable across a wide range of production and maintenance scenarios. The right-hand thread direction and 3A fit class ensure predictable torque and engagement in standard tapped holes.

Key Features

• Button head profile with 0.132-inch head height for low-clearance installations
• 5/32-inch hex socket drive compatible with standard hex keys and socket drivers
• Alloy steel construction rated at 38 HRC hardness
• Black oxide finish for moderate corrosion resistance and reduced reflectivity
• Fully threaded 3/8-inch length under head, 1/4-20 UNC right-hand thread
• Meets ANSI/ASME B18.3 and ASTM F835 fastener standards

Compatibility

Designed as a standard 1/4-20 UNC button socket cap screw for use in any application requiring ANSI/ASME B18.3-compliant inch-series socket fasteners with a button head profile.

Installation Notes

Installation requires a 5/32-inch hex key or socket driver. Power down and de-energize any equipment before servicing fasteners on live assemblies. Confirm the mating tapped hole meets 1/4-20 UNC thread standards before installation to ensure proper fit class engagement. Do not exceed the rated hardness limits of mating materials when applying torque.