S-91099A165 4-40 x 3/8" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws
Stainless Steel Phillips 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 passivated 18-8 stainless steel construction, ideal for harsh industrial environments
- Enhanced driving efficiency through Phillips No. 1 drive design, reducing cam-out and tool slippage during installation
- Reliable flush mounting with 82° countersink angle and undercut flat head profile for secure, vibration-resistant seating
- Consistent thread engagement with Class 2A UNC coarse threads ensuring precise fit and easy assembly
- High mechanical strength delivering 80,000 psi tensile strength and Rockwell B80 hardness for demanding applications
- Full-length threading providing maximum grip and load distribution across the entire 3/8" length
- Regulatory compliance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH
Professional Applications & Engineering Value
These 4-40 UNC flat head screws deliver critical performance advantages in precision assembly applications where corrosion resistance and flush surface requirements are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for electronics enclosures, machinery panels, and marine components. The combination of fully threaded design and Class 2A thread fit ensures reliable fastening in thin materials and tight spaces, while the undercut flat head with 82° countersink prevents surface protrusion in critical flush-mount applications. These industrial fasteners solve common challenges of vibration loosening and material compatibility while maintaining consistent performance in demanding environments.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit and UNC coarse threads (4-40 size). Complies with ASME B18.6.3 specifications for dimensional accuracy and performance. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) requirements. Features right-hand threading and full threading along the 3/8" length for maximum fastening capability.
