S-91266A109 4-40 x 1/4" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws
Alloy Steel Thread-Locking Hex Drive Flat 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
- Superior vibration resistance with nylon patch thread locker that maintains secure fastening in high-stress environments
- Exceptional tensile strength of 130,000 psi ensures reliable performance in demanding industrial applications
- Wide temperature tolerance from -65° to 250°F allows consistent performance across diverse operating conditions
- Precise Class 3A thread fit provides superior engagement and reduces the risk of cross-threading during installation
- Corrosion-resistant black-oxide coating on alloy steel extends service life in challenging environments
- Optimized 82° countersink angle ensures flush mounting and clean aesthetic finish in precision assemblies
- Hex drive design enables high-torque installation without cam-out for efficient assembly operations
Professional Applications & Engineering Value
These 4-40 UNC flat head screws with nylon patch locking technology solve critical fastening challenges in industrial equipment, electronic enclosures, and precision machinery. The black-oxide alloy steel construction combined with Class 3A thread fit ensures reliable performance where vibration resistance and dimensional accuracy are paramount. The fully threaded coarse UNC pattern provides maximum engagement in thin materials, while the temperature-resistant nylon patch maintains locking integrity across extreme thermal cycles. These features make them ideal for applications requiring secure, permanent fastening in aerospace, automotive, and heavy equipment assemblies where disassembly is not anticipated.
Specification Summary & Compliance
Manufactured to precise Class 3A thread fit standards with UNC coarse threading and 82° countersink angle. Fully compliant with ASTM F835 specifications for mechanical properties and dimensional requirements. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for restricted substance control. The black-oxide surface treatment provides corrosion protection while maintaining dimensional integrity per industrial fastening standards.
