S-91266A108 4-40 x 3/8" 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
- Vibration-resistant locking with permanent nylon patch thread locker that maintains secure fastening from -65° to 250°F
- Exceptional tensile strength of 130,000 psi ensures reliable performance in high-stress applications
- Superior corrosion protection through black-oxide coating on alloy steel for extended service life
- Precise thread engagement with Class 3A fit and UNC coarse threads for easy installation and secure holding power
- Optimized drive efficiency with 1/16" hex drive providing positive torque transmission and reduced cam-out risk
- Full-thread design delivers maximum grip length and uniform stress distribution along the entire fastener
- Industry compliance assurance meeting ASTM F835 specifications for consistent quality and performance
Professional Applications & Engineering Value
These 4-40 UNC flat head screws with nylon patch thread locker provide engineered solutions for vibration-prone industrial environments where fastener integrity is critical. The black-oxide alloy steel construction offers excellent corrosion resistance while maintaining the 130,000 psi tensile strength required for demanding applications in machinery, electronics, and automotive assemblies. The permanent thread locking technology eliminates the need for additional locking hardware, reducing assembly time and costs while ensuring reliable performance across a wide temperature range from -65° to 250°F. The fully threaded design with Class 3A thread fit guarantees precise engagement and consistent clamping force, making these flat head screws ideal for applications requiring flush mounting and reliable vibration resistance.
Specification Summary & Compliance
This 4-40 UNC flat head screw features precise Class 3A thread fit with UNC coarse threading and full thread coverage. Manufactured to ASTM F835 specifications, the fastener delivers consistent dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial sectors. The combination of Rockwell C39 hardness and controlled manufacturing processes guarantees reliable performance in critical applications where fastener integrity cannot be compromised.
