S-91771A541 1/4"-20 x 7/8" 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 mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Precision thread engagement through UNC coarse threading and Class 2A fit ensures secure fastening and vibration resistance
• Optimized flush mounting with standard 82° countersink angle and flat head design for seamless surface integration
• Efficient installation with No. 3 Phillips drive providing positive torque transfer and reduced cam-out risk
• Full-threaded design maximizes grip length and distributes stress evenly across the entire fastener
• Regulatory compliance meets ASME B18.6.3 specifications and environmental standards for global industrial use

Professional Applications & Engineering Value

These 1/4"-20 flat head Phillips screws deliver critical performance advantages in demanding applications where material integrity and precise fit are paramount. The passivated 18-8 stainless steel construction provides excellent resistance to oxidation and chemical exposure, making them ideal for marine equipment, food processing machinery, and outdoor structures. The UNC coarse threading with Class 2A fit ensures rapid assembly and reliable thread engagement in various materials, while the 82° countersink angle creates a flush surface finish that eliminates protrusions in precision assemblies. With full threading along the 7/8" length, these screws distribute clamping forces evenly, reducing stress concentration points that can lead to material failure in high-vibration environments like automotive components and industrial machinery.

Specification Summary & Compliance

This fastener maintains Class 2A thread fit tolerances with UNC coarse threading (1/4"-20) and right-hand thread direction. Manufacturing conforms to ASME B18.6.3 specifications, ensuring dimensional accuracy and interchangeability. The screw is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming environmental safety and restricted substance adherence for global industrial distribution and use.