S-94383A280 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Enhanced Durability & Strength: Alloy steel construction with 140,000 psi tensile strength and 84,000 psi shear strength ensures reliable performance under high-stress conditions.
• Superior Corrosion Resistance: Black oxide finish provides excellent protection against rust and wear, extending service life in harsh environments.
• Precise Alignment & Secure Fit: Class 3A thread fit and standard shoulder fit guarantee tight tolerances for accurate component positioning and reduced vibration.
• Easy Installation & Removal: Knurled socket head with 5/32" hex drive offers improved grip and prevents tool slippage during assembly.
• Wide Industrial Compatibility: UNC coarse threads and 1/4"-20 size ensure compatibility with standard components, simplifying inventory and replacements.
• High Load-Bearing Shoulder: 1 1/2" shoulder length with tight diameter tolerance provides stable support for rotating parts and pivoting mechanisms.
• Regulatory Compliance: Meets ASME B18.3, ASTM A574, RoHS 3, and REACH standards for safe, environmentally conscious use in global markets.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and durability challenges in industrial machinery. The Class 3A thread fit and precise shoulder diameter tolerance (-0.004" to -0.002") ensure minimal play, reducing wear in assemblies like rotating shafts, linkages, and jigs. The black oxide finish combats corrosion in humid or chemical-exposed environments, while the knurled socket head allows for secure torque application without stripping. Ideal for precision equipment, automotive fixtures, and conveyor systems, it maintains 140,000 psi tensile strength to withstand dynamic loads, ensuring long-term reliability and reduced maintenance costs.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 and ASTM A574 specifications, with UNC coarse threads in a 1/4"-20 size and Class 3A fit for high-precision engagement. The shoulder features a diameter of 5/16" (tolerance: -0.004" to -0.002") and length of 1 1/2" (tolerance: -0.005" to 0.005"), ensuring consistent performance. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible manufacturing and use.