S-91259A175 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Enhanced Durability: Alloy steel construction with Rockwell C32 hardness ensures long-lasting performance in demanding industrial environments.
• Superior Corrosion Resistance: Black oxide finish provides reliable protection against rust and wear, extending service life.
• Precision Thread Fit: Class 3A thread fit guarantees tight, secure fastening with minimal risk of loosening under vibration.
• High Load Capacity: 140,000 psi tensile strength and 84,000 psi minimum shear strength support heavy-duty applications without failure.
• Easy Installation & Removal: Hex socket drive with 5/32" size and knurled head allows for quick, slip-resistant tool engagement.
• Accurate Shoulder Alignment: Tight shoulder diameter and length tolerances ensure precise component positioning and reduced assembly errors.
• Broad Compliance: Meets ASME B18.3 and ASTM A574 standards, with RoHS 3 and REACH compliance for safe, global use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in machinery assembly, pivoting mechanisms, and precision equipment. The 1/4"-20 UNC coarse thread with Class 3A fit ensures rapid installation and high clamping force, reducing assembly time while maintaining integrity under dynamic loads. The black oxide finish enhances corrosion resistance in humid or abrasive settings, ideal for automotive, aerospace, and industrial automation. The knurled socket head and precise shoulder dimensions provide stable alignment for rotating parts, minimizing wear and misalignment issues. By combining high tensile strength with regulatory compliance, this screw delivers reliability in applications requiring repeatable precision and durability.

Specification Summary & Compliance

This shoulder screw features a 1/4"-20 UNC coarse thread with Class 3A precision fit, ensuring tight tolerances for secure fastening. Shoulder diameter and length adhere to strict tolerances (e.g., diameter: -0.004" to -0.002", length: -0.005" to 0.005") for accurate component positioning. Manufactured in compliance with ASME B18.3 and ASTM A574 specifications, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, guaranteeing safety and suitability for international industrial use.