S-92198A131 5/8"-18 x 6" ASME B18.2.1 18-8 Stainless Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance thanks to 18-8 Stainless Steel construction, ideal for harsh environments and long-term reliability.
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B70 hardness for demanding, high-stress applications.
• Precise and secure fastening ensured by the UNF fine thread and Class 2A thread fit, minimizing the risk of loosening under vibration.
• Optimized for high-clamp force applications with a partially threaded design that concentrates strength where it's needed most.
• Easy installation and removal with a standard external hex drive and 15/16" head width for common wrenching tools.
• Full regulatory compliance with ASME B18.2.1 standards, RoHS 3, and REACH, ensuring safety and environmental responsibility.
• Versatile 6-inch length provides ample engagement for thick materials and complex assemblies.

Professional Applications & Engineering Value

This 5/8"-18 UNF hex head screw is engineered to solve critical fastening challenges in industrial settings. The 18-8 Stainless Steel material provides excellent resistance to rust and corrosion, making it a durable choice for outdoor equipment, marine applications, and chemical processing plants where environmental factors degrade lesser materials. Its fine UNF thread and Class 2A thread fit offer superior vibration resistance and a tighter seal compared to coarse threads, which is crucial for machinery, heavy-duty structural frames, and precision assemblies. The partial threading design ensures that the unthreaded shank bears the shear load, preventing joint failure and maintaining clamp force integrity in dynamic or high-vibration environments. This combination of corrosion resistance, high tensile strength, and precision engineering delivers long-term reliability and reduces maintenance cycles.

Specification Summary & Compliance

This screw adheres to precise dimensional and performance standards. The thread is manufactured to a Class 2A fit for consistent, reliable engagement. It conforms to the ASME B18.2.1 specification for hex head screws, ensuring interchangeability and quality. The product is also verified to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety regulations for hazardous substances.