S-91264A554 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated nylon pellet locking that maintains secure fastening in dynamic environments.
• Exceptional tensile strength of 140,000 psi ensures reliable performance under heavy loads and stress.
• High-temperature stability with a locking temperature range from -50° to 250°F, suitable for varied industrial conditions.
• Precision Class 3A thread fit provides consistent engagement and reduces the risk of cross-threading in assembly.
• Durable black oxide finish offers corrosion resistance and extends service life in harsh applications.
• Easy installation and removal with a standard hex drive (5/32") and knurled head for improved grip.
• Compliance with ASME B18.3 and environmental standards (RoHS 3, REACH) ensures quality and regulatory adherence.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery, automotive assemblies, and heavy-duty equipment. The Class 3A UNC coarse threads and nylon pellet locking work together to prevent loosening under vibration, a common issue in rotating or high-motion systems. The black oxide finish enhances corrosion resistance, while the shoulder diameter and length tolerances ensure exact alignment in pivoting or spacing applications. With a Rockwell C32 hardness and 140,000 psi tensile strength, it delivers long-term reliability, reducing maintenance needs and downtime in industrial settings.

Specification Summary & Compliance

The screw features precision Class 3A thread fit with UNC coarse threading (1/4"-20) and shoulder diameter tolerance of -0.004" to -0.002". It meets ASME B18.3 specifications under ASTM A574 and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and manufacturing consistency.