S-91781A571 1/4"-20 x 3 1/2" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction and passivated finish, ideal for harsh industrial environments
• High tensile strength of 80,000 PSI ensures reliable performance in demanding mechanical applications
• Precise Class 2A thread fit guarantees smooth installation and secure fastening with UNC coarse threading
• 82° countersink angle provides flush mounting for clean, professional finishes in metal and wood assemblies
• Partially threaded design offers optimal grip and clamping force control for varied material thicknesses
• ASME B18.6.3 compliance ensures dimensional accuracy and interchangeability with standard components
• RoHS 3 and REACH compliance meets environmental regulations for global industrial supply chains

Professional Applications & Engineering Value

Engineered for precision industrial applications, these 1/4"-20 UNC flat head slotted screws deliver exceptional value in machinery assembly, electrical enclosures, and structural frameworks. The 18-8 Stainless Steel material combined with passivated finish provides lasting protection against chemical exposure and atmospheric corrosion, significantly reducing maintenance costs. The coarse thread spacing and partial threading enable rapid installation in thick materials while preventing joint loosening under vibration. With Rockwell B80 hardness and standardized flat head profile, these screws maintain dimensional stability in high-stress environments, making them ideal for OEM manufacturing and MRO operations requiring reliable stainless steel fasteners.

Specification Summary & Compliance

This 3 1/2" length flat head screw features Class 2A thread fit with UNC coarse threading (1/4"-20) and standard 82° countersink angle. Manufactured to ASME B18.6.3 specifications for dimensional accuracy. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations.