S-91263A551 1/4"-20 x 3/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws
Alloy Steel Hex Drive Flat 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 130,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from zinc plating protects against rust and extends service life in harsh industrial environments.
- Precision Class 3A thread fit provides secure, vibration-resistant connections, minimizing loosening in dynamic assemblies.
- 82° countersink angle and flat head design allow for flush mounting, creating a smooth surface finish and improved aesthetics.
- Hex drive (5/32") compatibility enables easy installation with standard tools, speeding up assembly processes.
- Coarse UNC threading ensures quick engagement and reduced cross-threading, ideal for rapid production lines.
- Full threading along the 3/8" length offers maximum grip and adjustability in various material thicknesses.
Professional Applications & Engineering Value
This zinc-plated alloy steel flat head screw is engineered to address common industrial challenges, such as vibration-induced loosening and corrosion in demanding environments. The UNC coarse thread and Class 3A fit provide a tight, reliable seal that withstands dynamic loads, making it ideal for machinery, automotive assemblies, and structural frameworks. The 82° countersink angle ensures a flush fit, eliminating protrusions that could interfere with moving parts or safety standards. With a Rockwell C39 hardness and robust alloy steel construction, it delivers long-term durability, reducing maintenance frequency and downtime in heavy-duty applications.
Specification Summary & Compliance
This screw adheres to Class 3A thread fit for precise dimensional accuracy and features UNC coarse threading (1/4"-20) with a right-hand direction. Manufactured in compliance with ASTM F835 specifications, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safety and regulatory conformity for global industrial use.
