S-91247A440 5/8"-18 x 3" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws
Medium-Strength Grade 5 Steel Hex 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 load-bearing capacity with 120,000 psi tensile strength, ideal for heavy-duty applications requiring reliable performance under stress.
- Superior corrosion resistance provided by zinc plating, extending service life in various industrial environments.
- Precise thread engagement with Class 2A fit and UNF fine threading, ensuring secure fastening and reduced risk of loosening.
- High durability from Rockwell C25 hardness, maintaining structural integrity under repeated use and high torque.
- Easy installation and removal with external hex drive and standard 15/16" head width, compatible with common tools for efficient assembly.
- Optimized for partial threading allowing unthreaded shank sections to bear shear loads effectively in structural joints.
- Compliance with industry standards including ASME B18.2.1 and SAE J429, ensuring consistent quality and interchangeability.
Professional Applications & Engineering Value
These Grade 5 hex head screws are engineered to address critical challenges in industrial assembly, such as vibration resistance and long-term reliability. The zinc plated steel construction provides a protective barrier against rust and corrosion, making them suitable for outdoor equipment, machinery frames, and automotive components. With UNF fine threads and Class 2A thread fit, they deliver precise torque control and minimize the risk of cross-threading in high-precision applications. The partial threading design enhances shear strength, ideal for securing flanges, brackets, and structural supports where load distribution is essential. By meeting ASME B18.2.1 specifications, these screws ensure compatibility and performance in demanding environments, reducing maintenance needs and downtime.
Specification Summary & Compliance
This fastener features a 5/8"-18 UNF thread size with Class 2A tolerance for accurate fit, and a 3" length with minimum thread length of 1 1/2". It complies with ASME B18.2.1 and SAE J429 standards, and is certified RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant for environmental safety.
