S-91771A535 1/4"-20 x 3/8" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh industrial environments
• Superior holding power achieved through full threading and UNC coarse threads for maximum grip in various materials
• Reliable flush installation featuring an undercut flat head with 82° countersink angle for secure, vibration-resistant seating
• Optimized drive performance with Phillips No. 3 drive style ensuring efficient installation and reduced cam-out risk
• High mechanical strength delivering 80,000 psi tensile strength and Rockwell B80 hardness for demanding applications
• Precision thread compatibility with Class 2A thread fit ensuring consistent engagement and reliable fastening
• Regulatory compliance assurance meeting ASME B18.6.3 standards and environmental regulations for global industrial use

Professional Applications & Engineering Value

Engineered for industrial machinery assembly and precision equipment manufacturing, these flat head Phillips machine screws solve critical fastening challenges where surface flushness and corrosion resistance are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against chemical exposure and atmospheric corrosion, while the fully threaded UNC coarse threading ensures rapid installation and superior pull-out resistance in metal assemblies and composite materials. The undercut flat head profile with 82° countersink angle prevents surface protrusion in countersunk holes, making these high-tensile strength screws ideal for automotive components, electrical enclosures, and marine hardware where vibration resistance and aesthetic finish are critical engineering requirements.

Specification Summary & Compliance

This 1/4"-20 x 3/8" machine screw maintains precision Class 2A thread fit with UNC coarse threading according to ASME B18.6.3 manufacturing specifications. The fastener features complete compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for international industrial supply chains. Manufacturing controls guarantee consistent dimensional accuracy across all critical parameters including head diameter, thread spacing, and countersink geometry.