S-91771A544 1/4"-20 x 1 1/4" 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 mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable, long-term performance
• Precision thread engagement through Class 2A UNC coarse threads ensuring secure fastening and vibration resistance
• Optimized installation efficiency with Phillips No. 3 drive and standard 82° countersink angle for flush mounting
• Full-threaded design providing maximum grip length and load distribution across the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH
• Versatile right-hand threading compatible with standard industrial equipment and maintenance procedures

Professional Applications & Engineering Value

These 1/4"-20 UNC flat head screws deliver critical performance advantages in demanding applications where corrosion resistance and structural integrity are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against chemical exposure and atmospheric corrosion, making these Phillips drive screws ideal for marine equipment, food processing machinery, and outdoor industrial installations. The fully threaded design ensures maximum thread engagement in both thin and thick materials, while the standard 82° countersink angle creates seamless flush mounting in precision assemblies. Engineered to ASME B18.6.3 standards, these flat head machine screws offer reliable performance in vibration-prone environments where loosening prevention is critical.

Specification Summary & Compliance

Manufactured to exacting dimensional standards with Class 2A thread fit tolerance for consistent mating with corresponding nuts and threaded holes. The UNC coarse thread (1/4"-20) provides rapid assembly and superior resistance to cross-threading. Compliance with ASME B18.6.3 ensures dimensional interchangeability and mechanical performance. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted substances. The combination of 80,000 psi tensile strength and Rockwell B80 hardness guarantees mechanical reliability in demanding fastening applications.