S-91259A725 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capacity: With a tensile strength of 140,000 psi and minimum shear strength of 84,000 psi, this shoulder screw reliably handles high-stress applications without failure.
• Precision Alignment & Reduced Wear: The 1/2" diameter shoulder with tight tolerance ensures accurate component positioning, minimizing misalignment and extending equipment life.
• Superior Corrosion Resistance: Black oxide finish provides durable protection against rust and oxidation in harsh industrial environments.
• Enhanced Grip & Installation: Knurled socket head design offers improved tool engagement and prevents slipping during high-torque assembly.
• Reliable Thread Performance: Class 3A UNC coarse threads ensure secure fastening with excellent vibration resistance in demanding applications.
• Consistent Mechanical Properties: Alloy steel construction with Rockwell C32 hardness delivers predictable performance and durability across production runs.
• Regulatory Compliance Assurance: Meets ASME B18.3, ASTM A574, RoHS 3, and REACH standards for quality and environmental responsibility.

Professional Applications & Engineering Value

This 3/8"-16 UNC shoulder screw delivers critical engineering value in precision assembly applications where alignment and rotational control are paramount. The alloy steel construction with black oxide finish provides both the strength for heavy-duty operations and corrosion resistance for longevity in manufacturing environments. The precisely machined 1/2" shoulder diameter with tight tolerances acts as a permanent spacer or pivot point in machinery, eliminating the need for additional components and reducing assembly complexity. The knurled socket head ensures secure tool engagement during installation, particularly important in high-vibration applications common in industrial equipment, automotive assemblies, and precision manufacturing fixtures. The Class 3A thread fit maintains consistent clamping force while the coarse UNC thread profile facilitates quicker assembly in production settings.

Specification Summary & Compliance

This shoulder screw maintains Class 3A thread fit with UNC coarse threading (3/8"-16) and features precise shoulder dimensions (1/2" diameter with -0.004" to -0.002" tolerance, 3-1/4" length with -0.005" to 0.005" tolerance). Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel with Rockwell C32 hardness. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets.