S-91783A107 4-40 x 5/16" ASME B18.6.3 Stainless Steel Round Head Slotted Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 18-8 stainless steel construction and passivated finish for long-term reliability in harsh environments
• Superior mechanical strength delivering 100,000 psi tensile strength and Rockwell B100 hardness for demanding industrial applications
• Precision threading with Class 2A fit and UNC coarse thread profile ensuring secure, vibration-resistant fastening
• Full-threaded design providing maximum engagement and holding power across the entire screw length
• Standard slotted drive offering compatibility with common tools for straightforward installation and maintenance
• Rounded head profile creating a finished appearance while distributing clamping force effectively
• Regulatory compliance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

These 4-40 UNC rounded head slotted screws deliver exceptional performance in precision assembly applications where corrosion resistance and mechanical reliability are critical. The 18-8 stainless steel material combined with passivated finish provides superior protection against oxidation and chemical exposure, making them ideal for electronics enclosures, instrumentation, marine equipment, and food processing machinery. The fully threaded design with coarse UNC threading ensures maximum thread engagement and prevents loosening under vibration, while the Class 2A fit maintains precise dimensional accuracy for consistent assembly operations. These industrial-grade fasteners solve common challenges of fastener failure, corrosion-induced degradation, and installation inconsistency in demanding B2B environments.

Specification Summary & Compliance

This 4-40 UNC screw features precise Class 2A thread fit with right-hand threading and standardized dimensions per ASME B18.6.3 manufacturing specifications. The fastener maintains dimensional accuracy with 5/16" length, 0.112" thread diameter, and standard rounded head profile. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial sectors while meeting international quality standards for mechanical fasteners.