S-91266A581 5/16"-18 x 3/4" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws
Alloy Steel Thread-Locking 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
- Vibration-resistant locking with nylon patch thread locker maintains secure fastening in temperatures from -65° to 250°F
- Superior load-bearing capacity from 130,000 psi tensile strength prevents failure under high-stress conditions
- Precision thread engagement with Class 3A fit ensures reliable installation and reduces cross-threading risks
- Enhanced corrosion resistance through black-oxide coating extends service life in demanding environments
- Optimized drive transfer with hex drive design provides maximum torque application without cam-out
- Full-thread engagement along entire 3/4" length delivers consistent clamping force across the joint
- Industry compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for quality and environmental safety
Professional Applications & Engineering Value
These black-oxide alloy steel flat head screws with 5/16"-18 UNC coarse threading deliver exceptional performance in vibration-prone industrial applications. The integrated nylon patch thread locker effectively prevents loosening in machinery, automotive assemblies, and electrical enclosures where thermal cycling from -65° to 250°F occurs. The Class 3A thread fit ensures precise installation in tapped holes while the 82° countersink angle provides flush mounting in standard chamfered surfaces. With fully threaded design and hex drive configuration, these high-strength fasteners offer reliable clamping force distribution and easy installation in confined spaces, making them ideal for manufacturing equipment, structural frameworks, and maintenance operations requiring durable, vibration-resistant fastening solutions.
Specification Summary & Compliance
These flat head screws feature precision Class 3A thread fit with 5/16"-18 UNC coarse threads and right-hand threading. Manufacturing complies with ASTM F835 specifications with full RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance. The black-oxide alloy steel construction provides Rockwell C39 hardness and maintains dimensional stability across the specified temperature range.
