S-91255A161 6-40 x 1/2" ASME B18.3 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
- Superior corrosion resistance with Black-Oxide Alloy Steel coating, extending service life in harsh industrial environments.
- Exceptional tensile strength of 120,000 psi ensures reliable performance in high-stress and heavy-duty applications.
- High-precision Class 3A thread fit provides secure, vibration-resistant fastening with minimal backlash.
- Fine UNF threading offers improved load distribution and superior holding power in precision assemblies.
- Fully threaded design allows for maximum grip length and adjustable positioning in varied material thicknesses.
- Rockwell C39 hardness delivers excellent wear resistance and durability under repetitive use.
- Compact rounded button head with 5/64" hex drive enables easy installation in confined spaces and reduces snagging risks.
Professional Applications & Engineering Value
Engineered for demanding industrial settings, this 6-40 UNF fine thread screw addresses critical challenges in precision machinery, electronics, and automotive assemblies. The Black-Oxide Alloy Steel construction combats rust and oxidation, maintaining integrity in humid or chemically exposed environments. Its Class 3A thread fit minimizes loosening from vibrations, a common failure point in dynamic systems. The rounded button head design provides a low-profile finish, preventing interference in compact device housings while the hex drive ensures secure tool engagement during high-torque installation. Ideal for applications requiring repeated disassembly, the screw’s high tensile strength and fine thread spacing offer reliable, long-term fastening solutions that reduce maintenance downtime and enhance product lifecycle.
Specification Summary & Compliance
This screw adheres to Class 3A thread tolerance per UNF (Unified National Fine) standards, ensuring precise dimensional accuracy. Manufacturing and material specifications comply with ASME B18.3 and ASTM F835 for consistent quality and performance. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety regulations for hazardous substance restrictions.
