S-91259A225 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Load-Bearing Capacity: Withstands up to 140,000 psi tensile and 84,000 psi shear forces, ensuring reliable performance in high-stress applications.
• Precision Thread Engagement: Class 3A thread fit guarantees tight tolerances and secure fastening, reducing the risk of loosening under vibration.
• Enhanced Durability & Corrosion Resistance: Black oxide finish on alloy steel provides improved wear resistance and protection against rust in harsh environments.
• Secure Grip & Easy Installation: Knurled head and 5/32" hex drive allow for firm handling and straightforward torque application with standard tools.
• Accurate Alignment & Stability: 3 1/2" shoulder length with minimal tolerances ensures precise component positioning and reduces misalignment issues.
• High Hardness for Longevity: Rockwell C32 hardness maintains structural integrity and resists deformation over repeated use.
• Regulatory Compliance & Safety: Meets ASME B18.3, RoHS 3, and REACH standards, ensuring environmental safety and industry acceptance.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial machinery, automation, and precision equipment. The 1/4"-20 UNC coarse thread with Class 3A fit ensures rapid assembly and reliable retention in dynamic environments, minimizing downtime. The black oxide finish enhances corrosion resistance, extending service life in humid or abrasive conditions. With a 3 1/2" shoulder length and tight diameter tolerances, it provides exact axial alignment for rotating parts like bearings and pulleys, reducing wear and vibration. Ideal for heavy-duty applications, it supports high tensile and shear strength requirements in manufacturing, automotive, and aerospace sectors, delivering consistent performance under extreme loads.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit per UNC standards, with shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005" for exacting assembly. Manufactured in compliance with ASME B18.3 specifications using ASTM A574 alloy steel, it ensures consistent quality. The product is RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, adhering to environmental and safety regulations for global industrial use.