S-91266A110 4-40 x 1/2" 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 nylon patch thread locker maintains secure fastening in temperatures from -65° to 250°F, preventing loosening in dynamic environments.
- Exceptional strength and durability from black-oxide alloy steel construction, delivering 130,000 psi tensile strength and Rockwell C39 hardness for heavy-duty applications.
- Precise thread engagement with Class 3A thread fit and UNC coarse threading ensures reliable installation and reduced cross-threading risks.
- Flush mounting capability with standard 82° countersink angle and flat head design allows for smooth surface finishes in assembled products.
- Easy installation and removal using a 1/16" hex drive, providing superior torque transfer and tool compatibility.
- Full-threaded design maximizes grip length and load distribution along the entire 1/2" length for enhanced holding power.
- Corrosion-resistant black-oxide finish improves longevity and appearance while meeting stringent ASTM F835, RoHS 3, and REACH compliance.
Professional Applications & Engineering Value
These 4-40 UNC flat head screws are engineered to address critical challenges in industrial assembly, such as vibration-induced fastener failure and material fatigue. The black-oxide alloy steel provides robust resistance to wear and environmental exposure, while the nylon patch thread locker ensures consistent performance across a wide temperature range (-65° to 250°F), making them ideal for automotive, electronics, and machinery applications. With a Class 3A thread fit and coarse thread spacing, they offer quick installation and reliable clamping force, reducing assembly time and maintenance costs. The fully threaded design and 82° countersink angle further enhance stability in precision components, delivering long-term reliability in demanding settings.
Specification Summary & Compliance
This screw adheres to Class 3A thread fit and UNC coarse thread standards with a 4-40 thread size and 1/2" length. It meets ASTM F835 specifications for mechanical properties and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity.
