S-91802A108 4-40 x 3/8" ASME B18.6.3 Stainless Steel Phillips Oval Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh industrial environments
• Superior holding power achieved through fully threaded UNC coarse thread design for maximum grip in various materials
• High tensile strength of 80,000 psi ensures reliable performance under heavy loads and vibration
• Consistent drive engagement with Phillips No. 1 drive style, reducing cam-out and improving installation efficiency
• Precise flush mounting capability thanks to standard oval head profile with 82° countersink angle
• Durable Rockwell B80 hardness maintains thread integrity and prevents stripping during repeated use
• Broad regulatory compliance including ASME B18.6.3 standards for dimensional accuracy and RoHS 3/REACH for environmental safety

Professional Applications & Engineering Value

These 4-40 UNC oval head Phillips flat head screws deliver critical performance advantages in demanding applications where corrosion resistance and reliable fastening are paramount. The passivated 18-8 stainless steel construction provides excellent protection against rust and chemical exposure, making them ideal for electronics enclosures, machinery panels, and outdoor equipment. The combination of Class 2A thread fit and coarse threading ensures quick assembly and secure fastening in softer materials or where vibration resistance is required. The fully threaded design maximizes thread engagement throughout the entire 3/8" length, while the Phillips No. 1 drive offers familiar, efficient installation with standard tools. These features collectively address common industrial challenges of material degradation, installation consistency, and long-term fastener reliability.

Specification Summary & Compliance

Manufactured to precise ASME B18.6.3 specifications with Class 2A thread fit tolerance for consistent dimensional accuracy. The UNC coarse thread (4-40) provides optimal performance in various materials. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental safety and material restrictions adherence. Mechanical properties include 80,000 psi tensile strength and Rockwell B80 hardness for durable performance in industrial applications.