S-91772A908 4-40 x 2 3/8" ASME B18.6.3 Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction for extended service life in harsh environments
• Enhanced durability and strength with Rockwell B70 hardness and 70,000 psi tensile strength to withstand heavy-duty applications
• Reliable fastening performance through Class 2A thread fit and UNC coarse thread spacing for secure, vibration-resistant connections
• Optimized installation efficiency with Phillips #1 drive and rounded pan head design for easy tool engagement and reduced cam-out
• Versatile partial threading allowing precise clamping control where full thread engagement isn't required
• Compliance assurance meeting ASME B18.6.3 specifications for dimensional accuracy and manufacturing consistency
• Environmental responsibility with RoHS 3 and REACH compliance for safe use in regulated industries

Professional Applications & Engineering Value

These 4-40 UNC partially threaded pan head screws deliver exceptional engineering value in industrial fastening applications where corrosion resistance and mechanical strength are critical. The passivated 18-8 stainless steel construction provides superior protection against oxidation and chemical exposure, making them ideal for marine, food processing, and outdoor equipment applications. The partially threaded design allows for precise clamping force distribution, preventing damage to delicate materials while maintaining secure fastening. With Phillips #1 drive and rounded pan head profile, these screws offer improved installation efficiency and reduced operator fatigue in high-volume assembly operations. The combination of 70,000 psi tensile strength and Rockwell B70 hardness ensures reliable performance in vibration-prone environments, making them suitable for machinery, electronic enclosures, and automotive components where fastener integrity is paramount.

Specification Summary & Compliance

These inch-system fasteners feature 4-40 UNC coarse threads with Class 2A thread fit for consistent dimensional accuracy and proper mating with corresponding nuts and threaded holes. Manufacturing complies with ASME B18.6.3 standards ensuring precise head diameter (0.219"), head height (0.08"), and minimum thread length (1-1/2") specifications. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted substances for use in sensitive applications.