S-91259A464 1/4"-20 ASME B18.3, ASTM A108 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – 140,000 psi rating ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Precision Thread Fit – Class 3A thread tolerance provides secure, vibration-resistant connections for consistent assembly quality.
• Corrosion-Resistant Black Oxide Finish – Extends service life in demanding environments by preventing rust and degradation.
• Knurled Socket Head Design – Enhances grip during installation with standard hex drive, minimizing tool slippage and damage.
• Rigorous Shoulder Dimensions – 6" shoulder length with tight tolerances maintains accurate alignment in rotating assemblies and pivoting mechanisms.
• High Hardness Material – Alloy steel with Rockwell C32 hardness offers superior wear resistance and durability under repeated use.
• Coarse UNC Threading – 1/4"-20 thread facilitates quick assembly and disassembly, ideal for maintenance-heavy industrial equipment.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial machinery and precision equipment. The 6" shoulder length provides a stable bearing surface for rotating components, reducing wear on mating parts and ensuring smooth operation in conveyor systems, pivoting joints, and automation guides. The black oxide finish combats corrosion in humid or chemically exposed settings, while the UNC coarse thread and Class 3A fit deliver vibration resistance in high-cycle applications. By integrating a knurled socket head with hex drive, it enables secure torque application, preventing stripping and enhancing installation efficiency for maintenance teams. Ideal for use in assembly jigs, motor mounts, and robotic arms, this screw combines high tensile strength with dimensional precision to minimize downtime and extend equipment lifespan.

Specification Summary & Compliance

This shoulder screw maintains Class 3A thread fit per UNC standards with a shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005". It is manufactured in compliance with ASME B18.3 specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial supply chains.