S-98164A548 1/2"-20 x 1 1/2" ASME B18.3, ASTM F879 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh environments including marine and chemical applications
• Exceptional thread precision with Class 3A UNF fine threads ensuring reliable, vibration-resistant connections in critical assemblies
• High mechanical strength delivering 70,000 psi tensile strength and Rockwell B55 hardness for durable, long-lasting fastening performance
• Secure installation with 5/16" hex drive providing positive torque transmission and reduced cam-out risk during high-torque applications
• Full threading versatility allowing consistent engagement along the entire 1-1/2" length for adjustable positioning and maximum grip
• Optimized head design featuring a rounded button head with 0.875" diameter for reduced surface protrusion and improved aesthetics
• Regulatory compliance assurance meeting ASME B18.3, ASTM F879, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

These 316 stainless steel rounded head screws with UNF Class 3A threads solve critical challenges in precision engineering and industrial maintenance. The combination of fine thread spacing and passivated finish provides exceptional resistance to loosening under vibration while maintaining corrosion protection in demanding environments. Engineers specify these fully threaded hex drive screws for machinery assembly, marine equipment, and chemical processing systems where high tensile strength and dimensional stability are paramount. The rounded head profile minimizes stress concentration while the 5/16" drive size ensures compatibility with standard industrial tools, streamlining installation in confined spaces.

Specification Summary & Compliance

Manufactured to precise Class 3A thread fit tolerances per UNF standards with 1/2"-20 fine threading and full compliance with ASME B18.3 and ASTM F879 specifications. These screws meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets. Dimensional accuracy includes 0.875" head diameter, 0.265" head height, and consistent 1-1/2" length for reliable interchangeability.