S-91355A082 1/4"-20 x 3/4" ASME B18.3, ASTM F835 Steel Flanged Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with black-oxide coating, extending service life in demanding industrial environments.
• Superior load-bearing capacity from 120,000 psi tensile strength and Rockwell C39 hardness, preventing fastener failure under high stress.
• Quick and secure installation via the 5/32" hex drive and wide rounded button head, reducing assembly time and tool slippage.
• Reliable thread engagement with Class 3A UNC coarse threads, ensuring vibration resistance and easy alignment in various materials.
• Integrated flange design distributes clamping force evenly, eliminating the need for separate washers and simplifying inventory.
• Full threading along the 3/4" length provides maximum grip and adjustability in deep or variable-thickness applications.
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH, guaranteeing safety and regulatory acceptance for global supply chains.

Professional Applications & Engineering Value

This black-oxide alloy steel rounded head hex screw is engineered to address critical challenges in heavy machinery, automotive, and structural assemblies where vibration resistance and corrosion protection are paramount. The UNC coarse thread spacing and Class 3A thread fit enable rapid installation in steel, aluminum, and cast components, reducing labor costs while maintaining precise torque retention. The flanged design increases bearing surface area, preventing surface damage and loosening under dynamic loads. Ideal for high-stress applications such as engine mounts, conveyor systems, and construction equipment, this screw delivers consistent performance where tensile strength and environmental durability are non-negotiable.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread fit tolerances with UNC coarse thread spacing (1/4"-20), this screw adheres to ASME B18.3 dimensional standards. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free of hazardous substances. The fully threaded design and right-hand thread direction provide uniform stress distribution, meeting rigorous industrial fastener specifications for reliability and safety.