S-91259A427 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior load-bearing capacity with 140,000 psi tensile strength and 84,000 psi shear strength for demanding industrial applications
• Precision thread engagement with Class 3A fit and UNC coarse threads ensuring reliable fastening in high-vibration environments
• Enhanced corrosion resistance through black oxide finish protecting against rust and extending service life
• Optimized torque transmission with hex socket drive and knurled head texture preventing slippage during installation
• Consistent dimensional accuracy with controlled shoulder diameter and length tolerances for precise component alignment
• Exceptional durability from alloy steel construction and Rockwell C32 hardness maintaining performance under repeated stress
• Regulatory compliance assurance meeting ASME B18.3, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This alloy steel shoulder screw delivers critical engineering solutions where precision alignment and high-strength fastening are paramount. The black oxide finish provides essential corrosion protection for machinery operating in harsh environments, while the UNC coarse thread design ensures rapid assembly and superior resistance to vibration loosening. The precisely machined shoulder maintains accurate component positioning in rotating assemblies, pivot points, and guide mechanisms. With its hex socket drive and knurled head, installation torque is efficiently transferred without tool slippage, making it ideal for automated assembly systems. These shoulder screws are engineered to withstand extreme mechanical stresses in industrial equipment, automotive components, and precision manufacturing fixtures where failure is not an option.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit ensuring precise thread engagement. The shoulder diameter maintains tight tolerances (-0.004" to -0.002") with shoulder length controlled within -0.005" to 0.005" for consistent performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, meeting global regulatory requirements for industrial components.