S-91259A401 4-40 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi minimum shear strength for reliable performance in demanding applications
• Superior corrosion resistance provided by the black oxide finish, extending service life in harsh industrial environments
• Precise thread engagement with Class 3A fit and UNC coarse thread spacing ensuring secure fastening and vibration resistance
• Optimized material performance through alloy steel construction with Rockwell C32 hardness for durability and wear resistance
• Easy installation and removal with 5/64" hex socket drive allowing for high torque application in confined spaces
• Consistent dimensional accuracy with standardized shoulder diameter and length tolerances for precise component alignment
• Industry compliance assurance meeting ASME B18.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

This alloy steel shoulder screw with black oxide finish delivers critical engineering solutions for precision machinery and industrial equipment. The 4-40 UNC coarse thread with Class 3A fit provides superior vibration resistance in dynamic applications, while the 5/32" thread length ensures optimal engagement in thin materials. The socket head design with 5/64" hex drive enables high-torque installation in space-constrained assemblies. Engineered for precision shoulder screw applications requiring exact component positioning, the standardized shoulder diameter and length maintain consistent alignment in rotating mechanisms, pivoting joints, and guide assemblies. The combination of high tensile strength and corrosion-resistant finish makes it ideal for automotive, aerospace, and manufacturing equipment where reliability and longevity are paramount.

Specification Summary & Compliance

Manufactured to exacting standards, this shoulder screw features Class 3A thread fit per UNC specifications with precise dimensional tolerances for shoulder diameter (-0.004" to -0.002") and length (-0.005" to 0.005"). The component meets ASME B18.3 manufacturing specifications and complies with ASTM A574 material standards. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe use across global markets. The right-hand thread direction with coarse thread spacing provides reliable fastening performance in various industrial applications.