S-91205A108 4-40 x 3/8" ASME B18.3, ASTM A574 Alloy Steel Thread-Locking Socket Head Screws
Alloy Steel Thread-Locking 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
- Permanent vibration resistance with nylon patch thread locking that maintains secure fastening in high-stress environments
- Exceptional temperature stability with reliable performance across -70° to 250°F (-57° to 121°C) operating range
- Superior load-bearing capacity through 170,000 psi tensile strength and Rockwell C37 hardness for heavy-duty applications
- Precise thread engagement with Class 3A fit and UNC coarse threads ensuring consistent clamping force
- Enhanced corrosion protection from black-oxide coating on alloy steel for extended service life
- Optimized drive efficiency with hex socket design providing superior torque transmission and strip resistance
- Full regulatory compliance meeting ASME B18.3, ASTM A574, RoHS 3, and REACH standards for global industrial use
Professional Applications & Engineering Value
These 4-40 UNC socket head cap screws with nylon patch locking technology address critical vibration-induced loosening in industrial machinery, automotive assemblies, and precision equipment. The black-oxide alloy steel construction combined with Class 3A thread fit ensures dimensional stability under dynamic loads, while the temperature-resistant nylon patch thread locker maintains clamp force integrity across extreme thermal cycles. The hex drive socket head design enables high-torque installation in confined spaces, making these industrial fasteners ideal for applications requiring reliable performance in challenging environments where vibration resistance and mechanical strength are paramount.
Specification Summary & Compliance
Manufactured to ASME B18.3 specifications with ASTM A574 material standards, these screws feature Class 3A thread fit for precision engagement and UNC coarse threads for rapid assembly. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations ensures suitability for global industrial applications requiring restricted substance control.
