S-91737A069 4-40 x 3/16" ASME B18.6.3 Stainless Steel Fillister Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish for extended service life in harsh environments
• High tensile strength of 80,000 psi ensures reliable fastening performance under demanding mechanical loads
• Class 2A thread fit precision guarantees consistent assembly and interchangeability with standard components
• Fillister head design with Phillips drive provides enhanced torque transmission and reduced cam-out during installation
• Full threading along the 3/16" length delivers maximum engagement and holding power in various material thicknesses
• Rockwell B85 hardness rating maintains thread integrity and prevents deformation during repeated use
• Comprehensive regulatory compliance including ASME B18.6.3, RoHS 3, and REACH for global quality assurance

Professional Applications & Engineering Value

These 4-40 UNC rounded head Phillips screws deliver exceptional engineering value in precision assembly applications where corrosion resistance and mechanical reliability are critical. The combination of 18-8 stainless steel material with passivated finish provides superior protection against oxidation and chemical exposure, making them ideal for electronics enclosures, medical devices, and marine equipment. The fillister head profile offers optimal clearance while the coarse UNC threading ensures rapid installation and secure fastening in metals, plastics, and composite materials. Engineered to ASME B18.6.3 specifications, these fully threaded machine screws maintain consistent performance in vibration-prone environments, reducing maintenance requirements and downtime in industrial operations.

Specification Summary & Compliance

This 4-40 UNC screw features Class 2A thread fit tolerance for precision assembly, manufactured in compliance with ASME B18.6.3 standards. The product meets RoHS 3 (2015/863/EU) compliance for hazardous substance restriction and REACH (EC 1907/2006) requirements for chemical safety. With dimensions including 3/16" length, 0.183" head diameter, and No. 1 Phillips drive size, these screws ensure dimensional consistency across production batches for reliable industrial integration.