S-91253A601 5/16"-18 x 4" 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
- Superior corrosion resistance with black-oxide coating for extended service life in harsh industrial environments
- Exceptional tensile strength of 130,000 PSI ensures reliable performance under heavy loads and vibration
- Precision Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections
- 82° countersink angle allows for flush mounting in standard applications with clean, professional finishes
- Partial threading design offers optimal grip strength while reducing material stress concentrations
- Hex drive compatibility with 3/16" drive size enables efficient installation with standard tools
- Rockwell C39 hardness maintains structural integrity and prevents stripping during repeated use
Professional Applications & Engineering Value
These 5/16"-18 UNC flat head screws with black-oxide alloy steel construction address critical engineering challenges in industrial fastening. The coarse thread spacing and Class 3A thread fit ensure rapid installation while maintaining vibration resistance in machinery, structural frameworks, and heavy equipment applications. The partial threading design concentrates clamping force where needed most, preventing joint loosening under dynamic loads. The 82° countersink angle provides seamless integration into predrilled surfaces, making these heavy-duty fasteners ideal for manufacturing, construction, and automotive assembly where flush mounting and corrosion resistance are paramount. The combination of high tensile strength and controlled hardness makes these screws suitable for demanding applications requiring repeated disassembly and reassembly.
Specification Summary & Compliance
Manufactured to exacting Class 3A thread fit standards with UNC coarse thread spacing and 5/16"-18 thread size. These screws comply with ASTM F835 specifications for mechanical properties and dimensional requirements. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations. The right-hand thread direction and 4" length with 1 1/8" minimum thread length ensure consistent performance across industrial applications.
