S-91221A163 4-40 x 7/16" UL 94 HB Plastic Socket Head Screws

Key Features & Benefits at a Glance

• Enhanced Durability & Strength: Glass-filled nylon construction provides superior mechanical properties compared to standard plastics, offering excellent resistance to wear and impact in demanding industrial environments.
• Reliable High-Temperature Performance: Withstands operating temperatures from -20° to 230° F, ensuring stable performance in applications with thermal cycling without compromising structural integrity.
• Precise Thread Engagement: UNC coarse threads with Class 2A fit guarantee consistent, reliable fastening with reduced risk of cross-threading and simplified installation.
• Secure Hex Drive Compatibility: 3/32" hex drive socket head allows for high-torque application using standard tools, providing a secure, slip-resistant connection.
• Comprehensive Regulatory Compliance: Meets UL 94 HB flammability standards and is fully compliant with RoHS 3 and REACH regulations, ensuring safety and environmental responsibility.
• Corrosion & Chemical Resistance: Non-conductive, off-white glass-filled nylon material naturally resists corrosion, chemicals, and electrical isolation, ideal for electronic and corrosive environments.
• Lightweight & Fully Threaded Design: 7/16" length with full threading offers maximum grip length and weight reduction benefits while maintaining uniform stress distribution.

Professional Applications & Engineering Value

These 4-40 UNC glass-filled nylon socket head cap screws deliver critical engineering solutions where metal fasteners fall short. The glass-filled nylon plastic composition provides exceptional strength-to-weight ratio, making them ideal for industrial applications requiring vibration resistance, electrical insulation, and corrosion prevention. The coarse thread design with Class 2A thread fit ensures quick assembly and reliable performance in plastics and soft materials, while the hex drive socket head enables high torque application without stripping. Commonly used in electronics enclosures, automotive components, and machinery where temperature resistance from -20° to 230° F is crucial, these screws eliminate galvanic corrosion risks and meet stringent UL 94 HB safety standards.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with Class 2A thread fit tolerance ensuring consistent mating with UNC threaded components. These fully threaded screws comply with UL 94 HB flammability specifications and are verified RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental and safety regulations for industrial fastener applications.