S-91255A550 1/4"-28 x 1/4" ASTM F835 Steel Button Head Hex-Drive Screws
Steel Button Head Hex-Drive 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 of 120,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh industrial environments.
- Precise Class 3A thread fit provides tight, secure fastening with minimal play, ideal for vibration-prone assemblies.
- Fine UNF threading offers enhanced holding power and resistance to loosening compared to coarse threads.
- Fully threaded design allows for maximum grip along the entire length, improving load distribution.
- Hex drive compatibility with a 5/32" key enables easy installation and removal, even in confined spaces.
- Rounded button head profile reduces surface protrusion and provides a smooth, finished appearance.
Professional Applications & Engineering Value
This Black-Oxide Alloy Steel Rounded Head Screw is engineered to address critical challenges in precision machinery, automotive, and aerospace sectors where vibration resistance and corrosion protection are paramount. The UNF fine thread and Class 3A fit ensure minimal backlash and superior clamp load retention, preventing joint failure in dynamic loads. Its fully threaded construction and high tensile strength make it suitable for assemblies requiring uniform stress distribution and durability under extreme conditions. The hex drive facilitates quick servicing, while the rounded head minimizes snagging risks, making it a reliable choice for both OEM and MRO applications demanding long-term performance.
Specification Summary & Compliance
This screw adheres to ASME B18.3 and ASTM F835 specifications, ensuring dimensional accuracy and mechanical reliability. The Class 3A thread fit guarantees tight tolerances for precision assemblies. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in regulated industries without hazardous substances.
