S-91253A110 4-40 x 1/2" 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
- Superior corrosion resistance with black-oxide coating on alloy steel, extending service life in demanding industrial environments
- Exceptional mechanical strength with 130,000 PSI tensile strength and Rockwell C39 hardness for reliable performance under high stress
- Precision Class 3A thread fit ensures secure, vibration-resistant fastening in critical assemblies
- Optimized hex drive design with 1/16" drive size provides superior torque transmission and slip-resistant installation
- Industry-standard compliance with ASME B18.3 and ASTM F835 specifications guarantees consistent quality and interchangeability
- 82° countersink angle enables flush mounting in precision applications while maintaining structural integrity
- Environmental regulation compliance with RoHS 3 and REACH ensures safe usage across global markets
Professional Applications & Engineering Value
These 4-40 UNC flat head hex drive screws deliver exceptional engineering value in precision assembly applications where space constraints and reliability are critical. The black-oxide alloy steel construction provides superior corrosion protection while maintaining the high 130,000 PSI tensile strength required for demanding mechanical systems. The Class 3A thread fit with coarse spacing ensures rapid installation and vibration resistance in automotive, aerospace, and industrial equipment. The combination of fully threaded design and 82° countersink angle allows for perfect flush mounting in tight-tolerance applications, while the hex drive configuration prevents cam-out during high-torque assembly operations. These screws are engineered to solve common industrial challenges including fastener loosening, corrosion-induced failure, and installation inefficiency.
Specification Summary & Compliance
Manufactured to exacting Class 3A thread fit tolerances with UNC coarse thread spacing and right-hand threading. Complies with ASME B18.3 dimensional standards and ASTM F835 mechanical property requirements. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards. Features include: 1/2" length, 0.255" head diameter, fully threaded construction, and 82° countersink angle profile.
