S-91783A106 4-40 x 1/4" ASME B18.6.3 Stainless Steel Round Head Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength with 100,000 psi tensile strength and Rockwell B100 hardness for reliable load-bearing performance
• Precision thread engagement through Class 2A UNC coarse threads ensuring consistent fastening and vibration resistance
• Optimized installation efficiency with standard slotted drive and rounded head design for straightforward assembly
• Full-threaded construction providing maximum grip length and uniform stress distribution across the entire fastener
• Regulatory compliance assurance meeting ASME B18.6.3 specifications and environmental standards (RoHS 3, REACH)
• Right-hand thread direction with coarse spacing for quick installation and removal in time-sensitive operations

Professional Applications & Engineering Value

These 4-40 UNC rounded head slotted screws deliver critical performance advantages in precision assembly applications where corrosion resistance and mechanical reliability are paramount. The combination of 18-8 stainless steel material and passivated finish creates a robust barrier against oxidation and chemical exposure, extending service life in demanding environments from electronic enclosures to marine components. The fully threaded design with Class 2A thread fit ensures maximum thread engagement and clamping force distribution, effectively preventing loosening under vibration while the rounded head profile with slotted drive facilitates quick installation in confined spaces. Engineered to ASME B18.6.3 standards, these fasteners provide consistent dimensional accuracy for repeatable performance in automated assembly systems and precision equipment manufacturing.

Specification Summary & Compliance

This 4-40 UNC screw features precise Class 2A thread fit with coarse thread spacing and right-hand thread direction. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and performance standards. The product meets RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) environmental regulations, ensuring adherence to international restrictions on hazardous substances. Critical dimensions include 1/4" length, 0.211" head diameter, and fully threaded construction.