S-98164A685 1/4"-28 x 1 1/4" ASME B18.3, ASTM F879 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance in harsh environments due to 316 stainless steel construction and passivated surface treatment
• Superior thread engagement and vibration resistance with precision-machined UNF fine threads and Class 3A fit for reliable fastening
• High mechanical strength with 70,000 psi tensile strength to withstand demanding operational loads
• Easy installation and removal using standard 5/32" hex drive tools, reducing assembly time and tooling costs
• Smooth, low-profile rounded head design minimizes snagging risks and provides a finished appearance in visible applications
• Full threading along the 1 1/4" length ensures maximum grip and adjustability in various material thicknesses
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH for guaranteed quality and environmental safety

Professional Applications & Engineering Value

This 316 stainless steel rounded head screw delivers critical performance in corrosive or high-precision environments where fastener failure is not an option. The combination of UNF fine threading and Class 3A fit provides exceptional resistance to vibration loosening in machinery, automotive, and marine applications. The passivated finish enhances the natural corrosion resistance of 316 stainless steel, making these hex drive screws ideal for chemical processing equipment, food manufacturing, and offshore installations. With full compliance to ASME B18.3 specifications, engineers can specify these components with confidence for critical assemblies requiring predictable performance and regulatory adherence.

Specification Summary & Compliance

This screw features precision 1/4"-28 UNF fine threads with Class 3A thread fit for tight tolerances and reliable engagement. Manufactured to ASME B18.3 specifications where identified as ASTM F879, it ensures dimensional consistency and interchangeability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, containing no substances of very high concern above threshold limits. With a specified tensile strength of 70,000 psi and complete threading along its 1 1/4" length, this fastener meets rigorous industrial requirements for strength and application versatility.