S-91771A888 3-48 x 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 tensile strength of 80,000 PSI ensures reliable fastening under high-stress conditions
• Precise Class 2A thread fit guarantees smooth installation and secure mating with UNC coarse threads
• Undercut flat head design provides flush seating and prevents surface protrusion in countersunk applications
• Optimized Phillips No. 1 drive enables efficient installation with reduced cam-out risk
• Full threading along the 1/4" length ensures maximum grip and load distribution
• 82° countersink angle matches standard chamfered holes for seamless integration

Professional Applications & Engineering Value

These 3-48 UNC flat head screws deliver critical performance in precision assemblies where flush surface mounting is essential. The passivated 18-8 stainless steel construction provides excellent resistance to oxidation and chemical exposure, making them suitable for electronics enclosures, machinery panels, and automotive components. The undercut head profile eliminates gap formation while the coarse UNC threading ensures rapid installation in softer materials. With 80,000 PSI tensile strength and Rockwell B80 hardness, they maintain clamp force integrity in vibrating environments. The Phillips drive system offers familiar tool compatibility for maintenance teams, reducing installation time in high-volume production settings.

Specification Summary & Compliance

Manufactured to ASME B18.6.3 specifications with Class 2A thread tolerances for consistent fit. The UNC coarse thread (3-48) and right-hand direction follow standardized threading protocols. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental safety. The 82° countersink angle and fully threaded 1/4" length maintain dimensional accuracy across production batches.