S-91440A631 1/4"-20 x 5/8" ASME B18.6.3 Steel Round Head Combination Phillips/Slotted Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in harsh industrial environments
• Enhanced installation versatility with combined Phillips/Slotted No. 3 drive for compatibility with multiple tool types
• Optimized thread engagement through UNC coarse spacing and Class 2A fit ensuring reliable fastening in various materials
• Increased mechanical strength with Rockwell B70 hardness providing excellent resistance to deformation under load
• Maximum grip length from fully threaded design for superior holding power across the entire fastener length
• Streamlined assembly process with rounded head profile reducing installation time and improving workplace efficiency
• Regulatory compliance assurance meeting ASME B18.6.3 standards for consistent quality and performance

Professional Applications & Engineering Value

This zinc-plated steel rounded head screw delivers exceptional engineering value across industrial applications where corrosion resistance and mechanical reliability are paramount. The combination of UNC coarse thread spacing and Class 2A thread fit ensures rapid installation with minimal cross-threading risk in metal, wood, and composite materials. The dual Phillips/Slotted drive system provides installation flexibility for maintenance teams using different tool types, while the fully threaded design maximizes clamping force distribution. Engineered with Rockwell B70 hardness, this fastener maintains structural integrity under vibration and dynamic loads common in machinery assembly, electrical enclosures, and structural frameworks. The rounded head profile minimizes snagging hazards while providing sufficient bearing surface for secure fastening in automotive, construction, and manufacturing applications where both performance and safety are critical considerations.

Specification Summary & Compliance

This industrial-grade fastener features precise Class 2A thread fit with UNC 1/4"-20 coarse thread specifications and maintains dimensional accuracy per ASME B18.6.3 manufacturing standards. The product demonstrates full compliance with RoHS 3 (2015/863/EU) restrictions on hazardous substances and meets REACH (EC 1907/2006) requirements for chemical safety, ensuring environmental responsibility while delivering reliable mechanical performance in professional applications.