S-91099A477 1/4"-20 x 5/8" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh industrial environments
• Exceptional tensile strength of 80,000 PSI ensures reliable performance under high-stress applications
• Precision Class 2A thread fit provides smooth installation and secure fastening in UNC coarse threaded holes
• Optimized flush mounting with 82° countersink angle and undercut flat head design for seamless surface integration
• Enhanced drive stability through Phillips No. 3 drive system, reducing cam-out during installation
• Full threading along 5/8" length delivers maximum grip and uniform load distribution
• Industry compliance assurance meeting ASME B18.6.3 specifications for dimensional accuracy and performance

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these flat head Phillips machine screws provide critical solutions where surface flushness and corrosion resistance are paramount. The passivated 18-8 stainless steel construction withstands corrosive environments while maintaining structural integrity, making them ideal for machinery, electrical enclosures, and automotive assemblies. The UNC coarse threading with Class 2A fit ensures rapid installation and reliable engagement in various materials, reducing assembly time while preventing cross-threading. The undercut flat head profile with 82° countersink angle creates a secure, flush finish that eliminates protrusion issues in precision equipment. These fully threaded screws distribute clamping force evenly, preventing joint loosening in vibration-prone applications while the Rockwell B80 hardness maintains thread integrity through repeated use.

Specification Summary & Compliance

This 1/4"-20 x 5/8" flat head machine screw features precision UNC coarse threads with Class 2A fit tolerance ensuring consistent performance across industrial applications. Manufactured to ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming safe use across various industries. The 82° countersink angle and flat head undercut design meet industry standards for flush mounting requirements in precision assemblies.