S-91221A177 4-40 x 1/2" UL 94 HB Plastic Socket Head Screws

Key Features & Benefits at a Glance

• Superior chemical resistance from glass-filled nylon construction, ideal for harsh industrial environments
• Excellent electrical insulation properties for safe use in electrical assemblies and sensitive components
• Reliable performance across a wide temperature range (-20° to 230°F) without compromising integrity
• Precise Class 2A thread fit ensures smooth assembly and secure fastening in UNC coarse thread applications
• Durable hex drive design (3/32") provides secure tool engagement and reduces stripping risk
• Fully threaded shank offers maximum grip and adjustability across the entire 1/2" length
• Compliance with UL 94 HB, RoHS 3, and REACH standards guarantees safety and regulatory acceptance

Professional Applications & Engineering Value

This glass-filled nylon socket head cap screw delivers critical engineering advantages where metal fasteners fail. Its 4-40 UNC coarse thread and Class 2A fit provide reliable engagement in plastic and soft material assemblies, resisting vibration loosening. The black glass-filled nylon material inherently resists corrosion, chemicals, and moisture, eliminating galvanic corrosion risks in multi-material designs. It serves as an ideal electrical insulation screw in enclosures, control panels, and electronic devices. The hex drive socket head allows high-torque installation in confined spaces, while its operational range from -20° to 230°F ensures stability in both industrial and consumer applications requiring thermal cycling resistance.

Specification Summary & Compliance

This socket head cap screw features precise 4-40 UNC coarse threads with Class 2A tolerance for consistent fit. Manufacturing follows standardized socket head profile and fully threaded design specifications. The product is verified compliant with UL 94 HB flammability standards, RoHS 3 (2015/863/EU) for hazardous substance restrictions, and REACH (EC 1907/2006) regulations for chemical safety.