S-91259A489 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior load-bearing capacity with 140,000 psi tensile strength for demanding industrial applications
• Enhanced corrosion resistance through black oxide finish, extending service life in harsh environments
• Precision alignment ensured by Class 3A thread fit and controlled shoulder diameter tolerances
• Secure installation and removal with hex socket drive and knurled head for improved grip
• Reliable performance backed by ASME B18.3 compliance and alloy steel construction
• Optimized for high-vibration applications through UNC coarse threading and Rockwell C32 hardness
• Environmentally responsible manufacturing with full RoHS 3 and REACH compliance

Professional Applications & Engineering Value

This alloy steel shoulder screw delivers critical engineering solutions where precision shaft alignment and rotational stability are paramount. The black oxide finish provides essential corrosion protection for machinery operating in humid or chemically aggressive environments, while the 1/2" shoulder diameter maintains precise component positioning in assemblies. The UNC coarse threads ensure rapid installation and superior resistance to vibrational loosening in heavy equipment, automotive fixtures, and industrial automation systems. With its knurled socket head and hex drive compatibility, technicians can achieve high torque application without tool slippage, making it ideal for maintenance-critical applications where reliability cannot be compromised.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit for precision engagement. Shoulder diameter tolerance maintained at -0.004" to -0.002" with shoulder length tolerance of -0.005" to 0.005" for consistent dimensional accuracy. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, manufactured under ASTM A574 material specifications.