S-91251A078 4-40 x 1 1/4" ASTM A574 Alloy Steel Socket Head Screws
Alloy Steel 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
- Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in critical assemblies.
- Corrosion-resistant black-oxide finish on alloy steel enhances durability and longevity, even in demanding industrial environments.
- Precise Class 3A thread fit provides superior engagement and vibration resistance, minimizing loosening in dynamic applications.
- Partially threaded design allows for secure clamping where full threading isn't required, offering flexibility in various assembly setups.
- Standard hex socket drive with 3/32" size enables easy installation and high torque transmission without stripping.
- Compliance with ASTM A574 guarantees consistent quality and mechanical properties, ensuring repeatable performance.
- RoHS 3 and REACH compliance meets environmental regulations, making these screws suitable for global supply chains.
Professional Applications & Engineering Value
These 4-40 UNC Socket Head Cap Screws are engineered to address common industrial challenges such as vibration-induced loosening and corrosion. The black-oxide alloy steel construction, combined with a Class 3A thread fit, ensures tight tolerances and reliable fastening in machinery, automotive, and electronics assemblies. The partially threaded configuration allows for precise positioning and clamping force distribution, reducing stress concentrations. With a Rockwell C37 hardness and high tensile strength, these screws withstand heavy loads and repetitive stresses, making them ideal for applications requiring durability and precision, such as CNC equipment, enclosures, and structural frameworks.
Specification Summary & Compliance
This screw adheres to UNC coarse thread standards with a Class 3A thread fit for precise dimensional accuracy. It meets ASTM A574 specifications for alloy steel socket head cap screws, ensuring consistent mechanical properties. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it is free from restricted substances, supporting environmentally responsible manufacturing and usage in various industries.
