S-91266A561 1/4"-28 x 5/8" 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
- Permanent vibration resistance with nylon patch thread locker that maintains secure fastening under dynamic loads
- Superior corrosion protection through black-oxide coating on alloy steel, extending service life in harsh environments
- Precision thread engagement with Class 3A fit ensuring reliable performance in critical assemblies
- High-strength construction delivering 130,000 psi tensile strength for demanding mechanical applications
- Wide temperature tolerance from -65° to 250°F for stable performance across industrial operating conditions
- Optimized installation efficiency with hex drive design providing secure tool engagement and torque transmission
- Flush mounting capability with standard 82° countersink angle for smooth surface finishes
Professional Applications & Engineering Value
These nylon patch locking flat head screws solve critical vibration-induced loosening challenges in industrial equipment, machinery, and automotive assemblies. The black-oxide alloy steel construction combined with Class 3A UNF fine threads ensures precise fitment in high-stress applications where tolerance control is paramount. The permanent thread locking patch eliminates the need for separate locking components, streamlining assembly while maintaining integrity across the specified temperature range from -65° to 250°F. The fully threaded design and flat head profile make these fasteners ideal for applications requiring flush mounting in machinery frames, electronic enclosures, and precision instruments where both security and aesthetics matter.
Specification Summary & Compliance
Manufactured to exacting Class 3A thread fit standards with UNF 1/4"-28 fine threading and complete compliance with ASTM F835 specifications. The fasteners meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring they're suitable for global industrial applications. The combination of 130,000 psi tensile strength and Rockwell C39 hardness guarantees mechanical reliability in demanding environments.
