Value Collection 48240 Button Cap Screw 5-40 1/4in 100pk

Product Description

The VALUE COLLECTION 48240 is a 5-40 UNC button socket cap screw designed for precision fastening applications where a low-profile head and high clamping strength are required. Machined from alloy steel with a black oxide finish, this screw is fully threaded under the head and measures 0.25 inches in length under head. The button head style provides a domed, low-clearance profile driven by a 5/64 inch hex socket. With a hardness rating of 36-43 HRC and a 3A thread fit class, this fastener meets ANSI/ASME B18.3 and ASTM F835 standards. Each package contains 100 pieces.

This screw is suited for light mechanical assemblies, instrumentation, electronics enclosures, and other applications requiring a small-diameter, fine-pitch UNC fastener with a flush-friendly head profile. The black oxide finish provides mild corrosion resistance and reduces light reflection, making it appropriate for both indoor mechanical and OEM assembly environments. Machinists, millwrights, electronics assemblers, and maintenance technicians commonly work with this fastener size.

Key Features

• 5-40 UNC thread, right-hand direction, 3A fit class for precise thread engagement
• Button head profile with 5/64 inch hex socket drive for low-clearance installations
• Alloy steel construction with 36-43 HRC hardness for reliable clamping strength
• Black oxide finish for mild corrosion resistance and reduced surface reflectivity
• Fully threaded under head for maximum thread engagement in thin material
• Meets ANSI/ASME B18.3 and ASTM F835 fastener standards

Compatibility

Designed as a standard UNC 5-40 button socket cap screw compatible with any application or assembly specifying ANSI/ASME B18.3 geometry and a 3A thread fit class in that size.

Installation Notes

Install and remove using a calibrated 5/64 inch hex key or socket driver to avoid rounding the drive recess. Ensure mating threads are clean and free of debris before installation. Follow applicable industry torque guidelines for 5-40 alloy steel fasteners as specified in your assembly documentation. Power down or de-energize any equipment before servicing fasteners on electrical or mechanical assemblies.