S-91259A859 1/2"-13 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior load distribution with a precise 5/8" shoulder diameter that maintains alignment in high-stress assemblies
• Exceptional corrosion resistance through black oxide finish, extending service life in demanding industrial environments
• Reliable torque transmission with hex socket drive and knurled head for secure tool engagement and reduced slippage
• High-strength performance from alloy steel construction and Rockwell C32 hardness for heavy-duty applications
• Precision thread engagement with Class 3A UNC coarse threads ensuring secure fastening in high-vibration settings
• Extended shoulder length of 3-3/4" provides stable bearing surface for rotating components and precise spacing
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

This alloy steel shoulder screw delivers critical engineering solutions where precise alignment and rotational stability are paramount. The 3-3/4" shoulder length acts as a precision shaft for rotating components in machinery, while the Class 3A UNC coarse thread provides rapid assembly and superior vibration resistance. The black oxide finish creates a protective barrier against corrosion in harsh manufacturing environments, extending component life and reducing maintenance cycles. Engineered with Rockwell C32 hardness, this socket head shoulder screw maintains dimensional stability under heavy loads, making it ideal for precision equipment, industrial machinery, and automation systems where reliability cannot be compromised.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit with 1/2"-13 UNC coarse thread specifications and maintains tight tolerances on shoulder diameter (-0.004" to -0.002") and shoulder length (-0.005" to 0.005"). Manufactured in compliance with ASME B18.3 standards using ASTM A574 alloy steel, the screw meets stringent quality requirements. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe use across global industrial markets.