S-91670A537 1/4"-20 x 1/2" ASTM A574 Left-Hand Threaded Alloy Steel Socket Head Screws
Left-Hand Threaded 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.
- Superior thread fit with Class 3A tolerance provides precise engagement and vibration resistance, minimizing loosening in left-hand threaded assemblies.
- Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable, non-reflective finish suitable for industrial environments.
- High hardness rating of Rockwell C37 delivers excellent wear resistance and longevity, maintaining thread integrity through repeated use.
- Compliance with ASTM A574 specifications guarantees consistent quality and mechanical properties for critical engineering applications.
- Hex socket drive design allows for easy installation and high torque application in confined spaces, improving assembly efficiency.
- RoHS 3 and REACH environmental compliance ensures safe use in regulated industries without hazardous substances.
Professional Applications & Engineering Value
These left-hand thread socket head cap screws are engineered to address specific industrial challenges where reverse threading prevents unintentional loosening from rotational forces. The black-oxide alloy steel construction, combined with a Rockwell C37 hardness and 170,000 PSI tensile strength, ensures durability in high-vibration environments such as machinery, automotive systems, and rotating equipment. The UNC coarse thread design facilitates quick assembly and disassembly, while the hex drive allows for secure tightening in limited-access areas. Ideal for applications requiring reliable left-hand fastening solutions, these screws provide long-term performance and reduce maintenance needs in demanding sectors.
Specification Summary & Compliance
This screw features a 1/4"-20 UNC left-hand thread with Class 3A thread fit for precise dimensional accuracy. It is manufactured in accordance with ASTM A574 specifications, ensuring consistent mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, confirming the absence of restricted hazardous substances.
