S-91251A173 5-40 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 demanding applications.
- Class 3A thread fit provides superior precision and tighter tolerances for secure, vibration-resistant assemblies in critical machinery.
- Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable, low-glare finish suitable for industrial environments.
- Rockwell C37 hardness rating delivers excellent wear resistance and longevity, minimizing replacement needs and maintenance costs.
- Partially threaded design with 3/4" minimum thread length allows for flexible clamping and easier alignment in varied assembly setups.
- Compliance with ASTM A574, RoHS 3, and REACH standards guarantees material consistency, environmental safety, and global regulatory acceptance.
- Hex socket drive (3/32") and standard head profile enable easy installation with common tools, improving assembly efficiency and reducing labor time.
Professional Applications & Engineering Value
Engineered for precision and durability, this 5-40 UNC thread socket head cap screw addresses common industrial challenges such as vibration loosening and material fatigue. The black-oxide alloy steel construction, combined with a Class 3A thread fit, ensures secure fastening in high-vibration environments like automotive assemblies, machinery frames, and electronic enclosures. Its coarse thread spacing and partially threaded rod facilitate quick alignment and robust clamping, reducing installation errors. Ideal for industrial fasteners in OEM and MRO applications, it provides consistent performance where strength and regulatory compliance—such as RoHS and REACH—are critical for operational safety and longevity.
Specification Summary & Compliance
This screw adheres to inch system measurements with precise dimensions: 1-1/4" length, 0.205" head diameter, and 3/4" minimum thread length. It features UNC coarse threads with a Class 3A fit for tight tolerances, manufactured per ASTM A574 specifications. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), it meets environmental and safety standards for global industrial use.
