S-91259A157 4-40 ASTM A574 Shoulder Screws
Shoulder 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
- Exceptional strength and durability with 140,000 psi tensile and 84,000 psi shear strength, ideal for high-stress industrial applications.
- Precise Class 3A thread fit ensures reliable engagement and reduces the risk of cross-threading in assembly operations.
- Corrosion-resistant black oxide finish provides enhanced protection against rust and wear in harsh environments.
- Rockwell C32 hardness offers superior resistance to deformation under load, maintaining dimensional stability.
- 1/2" shoulder length with tight tolerances allows for accurate alignment and smooth rotation in machinery and pivoting mechanisms.
- Socket head with 5/64" hex drive enables easy installation and removal in confined spaces with standard tools.
- Compliance with ASTM A574, RoHS, and REACH guarantees material quality and environmental safety for global supply chains.
Professional Applications & Engineering Value
This 4-40 UNC thread shoulder screw is engineered to address critical challenges in precision assembly and mechanical systems. The alloy steel construction, combined with a black oxide finish, ensures long-term performance in demanding conditions such as robotics, automotive components, and electronic enclosures. The coarse UNC thread and Class 3A fit provide secure fastening with minimal risk of stripping, while the 1/2" shoulder length acts as a precise spacer or pivot point, reducing wear on moving parts. By integrating high tensile and shear strength, it supports heavy loads and vibrations, making it a reliable choice for industrial applications where failure is not an option.
Specification Summary & Compliance
The screw features a Class 3A thread fit per UNC standards, with shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005" for precise engineering. It meets ASTM A574 specifications for high-strength socket head cap screws and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safety and environmental responsibility.
