4-40 x 1 Brass Button Head Socket Cap Screw provides a brass socket-drive option for assemblies that need a broad bearing surface and a smoother head profile. The button-head geometry is chosen for reduced head projection and a smooth exposed appearance while keeping the head visible and accessible. Engineers choose brass here for electrical conductivity, non-magnetic behavior, and non-ferrous construction rather than high-strength structural loading.

Appropriate uses include machine covers and automation equipment, where internal hex drive access supports installation where side clearance for external tooling is limited. It can also fit instrumentation and precision equipment, where the finished button head keeps visible fastening points smooth while the material machines cleanly. 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 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 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.