S-91355A080 1/4"-20 x 3/8" ASME B18.3, ASTM F835 Steel Flanged Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional durability with 120,000 psi tensile strength and Rockwell C39 hardness for reliable performance in demanding applications
• Superior corrosion resistance through black-oxide coating on alloy steel, extending service life in harsh industrial environments
• Enhanced load distribution with integrated flange design, reducing surface pressure and preventing material damage
• Precise thread engagement with Class 3A UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized installation efficiency using standard 5/32" hex drive for quick assembly with common tools
• Full-thread design maximizes grip length and holding power across the entire fastener length
• Regulatory compliance meets ASME B18.3, RoHS 3, and REACH standards for global industrial applications

Professional Applications & Engineering Value

This black-oxide alloy steel rounded head screw delivers critical engineering solutions for industrial assembly challenges. The combination of 120,000 psi tensile strength and Rockwell C39 hardness provides exceptional resistance to shear forces and mechanical stress in heavy machinery, automotive components, and structural frameworks. The UNC coarse threading with Class 3A fit ensures rapid installation while maintaining precise tolerance control, significantly reducing assembly time in production environments. The flanged design eliminates the need for separate washers, providing superior clamping force distribution that prevents surface damage to connected materials. These industrial screws are particularly valuable in applications requiring repeated disassembly and reassembly, where the hex drive facilitates maintenance access in confined spaces while the black-oxide surface treatment protects against industrial corrosion factors.

Specification Summary & Compliance

This fastener maintains Class 3A thread fit precision according to ASME B18.3 specifications, ensuring consistent performance in critical applications. The 1/4"-20 UNC coarse thread configuration provides optimal engagement in various materials while the 3/8" length offers versatile fastening solutions. Manufacturing compliance includes ASME B18.3 dimensional standards, RoHS 3 (2015/863/EU) environmental directives, and REACH (EC 1907/2006) chemical substance regulations, guaranteeing suitability for international industrial markets and environmentally conscious manufacturing operations.