S-91253A311 1/4"-28 x 1 1/4" 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
- Exceptional Tensile Strength – Withstands up to 130,000 psi, providing reliable performance under high-stress conditions.
- Precision Class 3A Thread Fit – Ensures tighter tolerances and superior thread engagement for vibration-resistant assemblies.
- Durable Black-Oxide Coating – Enhances corrosion resistance and reduces galling in demanding environments.
- Fully Threaded UNF Fine Thread Design – Delivers increased clamping force and improved load distribution.
- 82° Countersink Angle – Allows for flush mounting, minimizing protrusion and improving aesthetics.
- Hex Drive Compatibility – Simplifies installation with standard 5/32" hex tools, reducing assembly time.
- High Hardness (Rockwell C39) – Resists wear and deformation, extending service life in repetitive applications.
Professional Applications & Engineering Value
Engineered for industrial and mechanical assemblies, these 1/4"-28 UNF Class 3A flat head screws address critical challenges such as joint integrity and environmental durability. The black-oxide alloy steel construction, combined with a fine right-hand thread and fully threaded design, ensures secure fastening in high-vibration settings like machinery, automotive systems, and precision equipment. The 82° countersink angle facilitates seamless integration into tapered seats, eliminating surface interference. Ideal for applications requiring high tensile strength and compliance with rigorous industry standards, these screws reduce maintenance needs and enhance long-term reliability.
Specification Summary & Compliance
This product adheres to Class 3A thread fit per UNF standards, ensuring precise dimensional accuracy. Manufactured in compliance with ASME B18.3 and ASTM F835 specifications, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The screw features a 1-1/4" length, 5/32" hex drive, and is fully threaded for consistent performance across industrial applications.
