S-91263A961 4-40 x 5/8" ASME B18.3 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 zinc-plated alloy steel construction for extended service life in demanding environments
- Exceptional holding power with 120,000 psi tensile strength ensuring reliable fastening under high-stress conditions
- Precise thread engagement with Class 3A fit providing superior vibration resistance and reduced loosening
- Efficient installation with 1/16" hex drive allowing quick assembly and disassembly with standard tools
- Optimal flush mounting with standard 82° countersink angle creating smooth, professional-looking surfaces
- Maximum thread contact with fully threaded design distributing load evenly across the entire fastener length
- Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations for global applications
Professional Applications & Engineering Value
These 4-40 UNC flat head screws deliver critical performance advantages for industrial assembly applications where vibration resistance and flush surface requirements are paramount. The zinc-plated alloy steel construction provides essential corrosion protection while maintaining the Rockwell C32 hardness needed for repeated installation cycles. The Class 3A thread fit ensures precise mating with tapped holes, eliminating play that can lead to equipment failure in precision machinery, electronic enclosures, and automotive components. The coarse thread spacing facilitates quicker installation in production environments while the 82° countersink angle guarantees proper seating in standard chamfered holes, preventing protrusion issues in confined spaces.
Specification Summary & Compliance
Manufactured to exacting ASME B18.3 specifications with Class 3A thread fit tolerances ensuring dimensional precision and reliable performance. The UNC coarse thread profile with right-hand direction follows industry standards for compatibility with existing tooling and components. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations guarantees these fasteners meet international safety and sustainability requirements for industrial applications.
