4-40 x 7/8 Alloy Steel Button Head Socket Cap Screw helps machine builders secure covers, brackets, and housings while keeping the head smooth and accessible. The alloy steel construction supports machine construction where the drawing calls for reduced head projection and a socket-drive button head.
Common installation points include control enclosures and equipment housings where the rounded head reduces sharp edges on handled surfaces. It may also be specified for robotics and packaging machinery when internal hex drive access supports repeatable assembly work in tight spaces. This head style is different from a standard socket head cap screw: it trades the taller cylindrical head form for a rounded button profile used on exposed assemblies.
When matching the 4-40 thread and 7/8 in. length, the reference head diameter is 0.201-0.213 in. and the head height is 0.051-0.059 in. The nominal body diameter and hex-key information below help confirm fit, tool clearance, and replacement requirements.
Reference dimensions may vary slightly by manufacturer.
Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.
