S-91259A642 5/16"-18 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Enhanced Durability - Alloy steel construction with Rockwell C32 hardness provides superior strength and wear resistance for long-lasting performance in demanding industrial environments.
• Precision Shoulder Alignment - 4" shoulder length with tight ±0.005" tolerance ensures accurate component positioning and smooth rotational movement in assemblies.
• Superior Corrosion Protection - Black oxide finish offers excellent rust resistance while maintaining dimensional stability in various operating conditions.
• High-Strength Thread Engagement - Class 3A thread fit with 5/16"-18 UNC coarse threads delivers reliable, vibration-resistant fastening in high-stress applications.
• Secure Installation & Removal - Hex socket drive with 3/16" drive size and knurled head provides positive grip for torque application while preventing tool slippage.
• Industry Standard Compliance - Meets ASME B18.3 specifications ensuring interchangeability and reliability across industrial equipment and machinery.
• Environmental Responsibility - RoHS 3 and REACH compliant construction eliminates hazardous substances while maintaining performance integrity.

Professional Applications & Engineering Value

This alloy steel shoulder screw delivers exceptional engineering value in applications requiring precise rotational movement and component alignment. The 4" shoulder length with tight manufacturing tolerances provides accurate bearing surfaces for pulleys, gears, and linkages, while the Class 3A thread fit ensures secure fastening in high-vibration environments. The black oxide finish protects against corrosion in industrial settings, extending service life in machinery, automation equipment, and precision instruments. The socket head design with hex drive allows for compact installation in confined spaces, making it ideal for assembly applications where accessibility is limited. These shoulder screws solve critical alignment and durability challenges in manufacturing equipment, robotics, and heavy machinery where precision and reliability are paramount.

Specification Summary & Compliance

This precision shoulder screw features 5/16"-18 UNC coarse threads with Class 3A thread fit for superior engagement. The shoulder maintains a diameter of 3/8" with tight tolerance of -0.004" to -0.002" and length of 4" with ±0.005" tolerance. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, it ensures dimensional consistency and performance reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications requiring strict regulatory adherence.