S-91221A128 3/8"-16 x 3/4" ASME B18.3, UL 94 HB Plastic Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance due to glass-filled nylon construction, ideal for harsh environments without risk of rust or galvanic corrosion.
• High tensile strength of 17,000 psi provides reliable clamping force and structural integrity for demanding assembly applications.
• Wide operating temperature range (-40°F to 200°F) ensures consistent performance and dimensional stability in both extreme cold and heat.
• Precise Class 2A thread fit with UNC coarse threads enables easy, fast assembly and reduces the risk of cross-threading.
• Standard hex socket drive (5/16") allows for high-torque installation and a clean, low-profile head design.
• Lightweight and electrically insulating properties make it perfect for applications where metal fasteners are unsuitable.
• Full compliance with ASME B18.3, RoHS 3, and REACH guarantees consistent quality, safety, and environmental responsibility.

Professional Applications & Engineering Value

This glass-filled nylon socket head cap screw is engineered to solve critical challenges in industries where metal fasteners fail. Its 3/8"-16 UNC coarse thread and Class 2A thread fit provide excellent engagement and vibration resistance in plastics, composites, and soft metals, preventing stripping and loosening. The off-white color and corrosion-resistant material make it ideal for food processing, medical devices, electronics, and outdoor equipment, eliminating contamination risks and electrical conductivity. With a temperature range from -40°F to 200°F and 17,000 psi tensile strength, it ensures long-term reliability in thermally dynamic and mechanically stressed assemblies, reducing maintenance and replacement costs.

Specification Summary & Compliance

This screw features a 3/8"-16 UNC coarse thread with a Class 2A thread fit for standard tolerance and easy assembly. It is manufactured in compliance with ASME B18.3 specifications for dimensional consistency. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring it meets stringent environmental and safety regulations for hazardous substances.