S-91221A217 4-40 x 1/2" UL 94 HB Plastic Socket Head Screws
Plastic Socket Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Corrosion-resistant construction using glass-filled nylon for long-lasting performance in harsh environments without rust or degradation
- Reliable temperature stability maintaining structural integrity across a wide operating range from -20°F to 230°F
- Precise Class 2A thread fit ensuring consistent engagement and secure fastening in industrial assemblies
- Standard hex drive compatibility with 3/32" drive size for easy installation using common Allen wrenches
- Comprehensive regulatory compliance meeting UL 94 HB flammability standards, RoHS 3, and REACH environmental directives
- Right-hand UNC coarse threading providing quick assembly and disassembly while resisting vibration loosening
- Non-conductive and lightweight properties ideal for electrical applications where metal fasteners could cause interference
Professional Applications & Engineering Value
These glass-filled nylon socket head cap screws deliver exceptional value in applications where corrosion resistance, electrical insulation, and weight reduction are critical engineering considerations. The 4-40 UNC coarse thread configuration ensures rapid installation in plastic components, electronic enclosures, and machinery where vibration resistance is paramount. The off-white color and plastic composition make these fasteners ideal for visible applications in consumer products, medical devices, and food processing equipment where metallic contamination must be avoided. With their hex drive design and fully threaded construction, these screws provide reliable clamping force while eliminating galvanic corrosion concerns in multi-material assemblies.
Specification Summary & Compliance
These socket head cap screws feature precise Class 2A thread fit per UNC standards with 4-40 thread size and 1/2" length. Manufacturing complies with UL 94 HB flammability rating for material safety, RoHS 3 (2015/863/EU) for hazardous substance restriction, and REACH (EC 1907/2006) compliance for chemical safety. The glass-filled nylon material maintains dimensional stability across the specified temperature range while providing consistent mechanical performance in industrial fastening applications.
