S-91255A564 1/4"-28 x 3/16" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in demanding industrial environments
• Precise Class 3A thread fit ensures secure fastening and vibration resistance in critical assemblies
• High tensile strength (120,000 psi) provides reliable performance under extreme mechanical stress
• Fine UNF threading delivers superior holding power and improved load distribution
• Rockwell C39 hardness maintains structural integrity and prevents thread deformation
• Low-profile rounded button head offers flush mounting while accommodating standard 5/32" hex tools
• Full threading design enables maximum engagement depth and versatile installation options

Professional Applications & Engineering Value

Engineered for precision assemblies requiring high-strength fastening solutions, these black-oxide alloy steel screws address common industrial challenges including vibration loosening, corrosion, and mechanical fatigue. The UNF fine thread configuration provides superior clamping force in thin materials and critical joints, while the Class 3A thread fit ensures consistent performance in automated production environments. Ideal for machinery, equipment manufacturing, and precision instrumentation, these rounded head screws combine the installation convenience of hex drive with the reliability of fully threaded design for maximum engineering efficiency.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread tolerances with UNF fine thread specification (1/4"-28). Complies with ASME B18.3 and ASTM F835 manufacturing standards. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance. All dimensions conform to inch system measurements with precise thread diameter of 0.25" and standardized head geometry.