S-91771A571 1/4"-20 x 3 1/2" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws
Stainless Steel Phillips Flat Head Screws
Image may differ from product. See technical specification for details.
Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
- Fast delivery
- Enjoy discounts on bulk purchases
- Secure Payment
- Fast Global Shipping
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 heavy-duty applications
- Reliable thread engagement through Class 2A UNC coarse threading, ensuring secure fastening in various materials
- Optimized flush mounting with standard 82° countersink angle and flat head design for smooth surface finishes
- Enhanced drive stability with Phillips No. 3 drive style, reducing cam-out during installation
- Controlled thread engagement through partial threading design, preventing over-tightening in precision assemblies
- Full regulatory compliance meeting ASME B18.6.3 specifications and environmental standards (RoHS 3, REACH)
Professional Applications & Engineering Value
These 1/4"-20 UNC flat head screws deliver critical engineering solutions where flush surface mounting and corrosion resistance are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for marine equipment, food processing machinery, and outdoor industrial applications. The partially threaded design ensures precise clamping force control, preventing damage to delicate components while the coarse UNC threading maintains secure fastening in softer materials and vibration-prone environments. With their 82° countersink angle and Phillips No. 3 drive, these screws facilitate quick installation and reliable performance in automated assembly lines and maintenance operations.
Specification Summary & Compliance
Manufactured to exacting ASME B18.6.3 standards with Class 2A thread fit tolerances for consistent performance. Features 1/4"-20 UNC coarse threads with minimum 1½" thread length and 3½" overall length. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets.
