4-40 x 1 1/4 Brass Button Head Socket Cap Screw fits applications where a rounded low-profile head and non-ferrous construction are both part of the design requirement. Compared with taller head styles, the rounded button head can reduce snag potential on panels, covers, and handled surfaces. The material is often selected when conductivity, machinability, and appearance are more relevant than the strength profile of alloy steel.

Appropriate uses include maintenance work and assembly operations, where the exact thread and length help match drawings, repair lists, and existing brass hardware. It can also fit architectural hardware and commercial brass components, where the rounded head provides a finished appearance on visible covers and trim. The internal hex drive supports socket-key installation in compact equipment without relying on an external wrenching surface.

For the 4-40 thread and 1 1/4 in. length, the reference head diameter is 0.201-0.213 in. and the head height is 0.051-0.059 in. Use the verified dimensions below when checking head projection, socket access, and replacement fit.

Technical Highlights

• Material: Brass
• Thread Size: 4-40
• Length: 1 1/4 in.
• Nominal Body Diameter: #4 (.112 in.)
• Head Diameter: 0.201-0.213 in.
• Head Height: 0.051-0.059 in.
• Hex-Key Size: 1/16 in.
• Drive Type: Internal Hex

Reference dimensions may vary slightly by manufacturer.