S-91255A159 6-40 x 3/8" 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 coating, extending service life in demanding industrial environments
- Exceptional tensile strength of 120,000 psi ensures reliable performance under high-stress applications
- Precision Class 3A thread fit provides superior engagement and vibration resistance in critical assemblies
- Rockwell C39 hardness rating maintains thread integrity and prevents stripping during repeated installations
- Hex drive compatibility allows for secure tool engagement and efficient installation in confined spaces
- Fully threaded design maximizes holding power along the entire fastener length for uniform load distribution
- Rounded button head profile offers a low-profile finish while preventing snagging in moving machinery
Professional Applications & Engineering Value
These 6-40 UNF Class 3A Black-Oxide Alloy Steel rounded head screws deliver exceptional engineering value in precision applications where reliability is paramount. The fine thread configuration provides superior resistance to vibrational loosening in machinery, electronic enclosures, and automotive components. The Black-Oxide surface treatment creates a protective barrier against corrosion while maintaining dimensional stability. Engineered with fully threaded UNF design, these screws ensure maximum thread engagement in thin materials and blind holes, solving common challenges of insufficient grip length. The combination of 120,000 psi tensile strength and Rockwell C39 hardness makes these fasteners ideal for high-stress applications requiring repeated disassembly without compromising thread integrity.
Specification Summary & Compliance
This precision fastener meets Class 3A thread tolerances for superior fit and consistent performance. Manufacturing complies with ASME B18.3 and ASTM F835 specifications, ensuring dimensional accuracy and material quality. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental standards. Features include right-hand UNF fine threads, 5/64" hex drive, and 3/8" length with standard rounded button head profile for consistent installation performance.
