S-91255A052 1/2"-20 x 3/4" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide finish for extended service life in harsh industrial environments
• Exceptional tensile strength of 120,000 psi ensures reliable performance under heavy loads and vibration
• Precision Class 3A thread fit provides superior engagement and eliminates cross-threading issues
• Fine UNF threading delivers enhanced clamping force and superior resistance to loosening
• Hex drive design with 5/16" drive size enables secure tool engagement and high torque application
• Rounded button head profile offers a low-profile, aesthetically pleasing finish while preventing snagging
• Full compliance with major industrial standards including ASME B18.3 and ASTM F835

Professional Applications & Engineering Value

This black-oxide alloy steel rounded head screw delivers exceptional engineering value in demanding applications where precision, strength, and corrosion resistance are critical. The Class 3A thread fit and UNF fine threading provide superior vibration resistance and clamping force, making it ideal for machinery, automotive assemblies, and precision equipment where loosening under dynamic loads is a concern. The black-oxide surface treatment creates a protective barrier against oxidation and environmental factors, significantly extending service life in industrial settings. With its rounded button head design and hex drive compatibility, this fastener combines easy installation with a clean, professional appearance, solving common challenges of fastener corrosion, thread stripping, and maintenance accessibility in heavy-duty applications.

Specification Summary & Compliance

This precision fastener features 1/2"-20 UNF fine threading with Class 3A fit for exceptional dimensional accuracy and thread engagement. Manufacturing complies with ASME B18.3 and ASTM F835 specifications, ensuring consistent quality and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, meeting the latest industry standards for hazardous substance restrictions and chemical safety.