S-91255A524 1/4"-20 x 9/16" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength (120,000 psi) ensures reliable performance in high-stress industrial applications, reducing failure risks
• Class 3A thread fit precision provides superior engagement and vibration resistance for secure, long-lasting assemblies
• Black-oxide coating on alloy steel enhances corrosion resistance and durability in demanding environments
• Rockwell C39 hardness maintains structural integrity under heavy loads and repeated use
• 5/32" hex drive design allows for easy installation with standard tools, improving assembly efficiency
• Fully threaded UNC coarse spacing enables faster installation and stronger holding power in various materials
• Comprehensive compliance with ASME B18.3, ASTM F835, RoHS 3 and REACH ensures quality and environmental safety

Professional Applications & Engineering Value

These 1/4-20 UNC rounded head screws deliver critical engineering solutions where vibration resistance, high tensile strength, and corrosion protection are paramount. The black-oxide alloy steel construction combined with Class 3A thread fit addresses common industrial challenges of joint loosening and material fatigue in heavy machinery, automotive assemblies, and structural frameworks. The button head profile with hex drive provides flush mounting where clearance is limited while maintaining high torque capability. Fully threaded with coarse UNC spacing, these fasteners offer superior pull-out resistance in metals, plastics, and composite materials, making them ideal for demanding industrial applications requiring reliable, long-term fastening solutions.

Specification Summary & Compliance

Manufactured to precise Class 3A thread fit tolerances per UNC standards with coarse thread spacing and right-hand threading. These rounded head screws comply with ASME B18.3 and ASTM F835 manufacturing specifications, ensuring dimensional accuracy and performance consistency. The product meets RoHS 3 (2015/863/EU) compliance for hazardous substance restrictions and REACH (EC 1907/2006) requirements for chemical safety, making them suitable for global industrial markets and environmentally conscious applications.