S-91771A309 12-24 x 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 for long-lasting performance in harsh environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for heavy-duty applications
• Precise thread engagement with Class 2A thread fit ensuring reliable fastening and vibration resistance
• Optimized drive efficiency featuring Phillips No. 3 drive for secure installation and reduced cam-out risk
• Versatile partial threading allowing for both clamping and alignment functions in various assembly scenarios
• Industry-standard compliance meeting ASME B18.6.3 specifications for consistent quality and interchangeability
• Environmental responsibility with full RoHS 3 and REACH compliance for safe use in regulated industries

Professional Applications & Engineering Value

These 12-24 UNC flat head screws deliver exceptional engineering value through their passivated 18-8 stainless steel construction and precision manufacturing. The 82° countersink angle ensures flush mounting in machinery, automotive, and industrial equipment applications where surface clearance is critical. The coarse UNC threading provides superior holding power in softer materials and faster installation times, while the partial threading design allows for both secure clamping and precise component alignment. With 4" length and Phillips No. 3 drive, these screws offer reliable performance in assembly lines, metal fabrication, and structural applications where corrosion resistance and mechanical integrity are paramount. The combination of 80,000 psi tensile strength and standardized dimensions makes them ideal for replacing worn fasteners in maintenance, repair, and operations (MRO) scenarios.

Specification Summary & Compliance

These industrial-grade flat head screws feature precision 12-24 UNC coarse threads with Class 2A thread fit for consistent dimensional accuracy and reliable performance. Manufacturing adheres to ASME B18.6.3 standards ensuring interchangeability and quality control. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making them suitable for use in electronics, automotive, and other regulated industries. The partially threaded design with 1½" minimum thread length provides optimal fastening characteristics while maintaining structural integrity throughout the 4" overall length.