S-91273A879 1/2"-13 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing performance
• Precise alignment and smooth rotation thanks to the 1-1/4" shoulder length with tight diameter tolerance for consistent pivot and bearing applications
• Easy installation and high torque transmission via the knurled socket head with 1/4" hex drive, reducing tool slippage
• Wide compatibility and secure fastening with 1/2"-13 UNC coarse threads and Class 2A fit, ensuring consistent engagement in various materials
• Enhanced durability under shear loads with minimum 35,000 psi shear strength, suitable for dynamic mechanical assemblies
• Compliance with global environmental standards including RoHS 3 and REACH, making it safe for regulated industries

Professional Applications & Engineering Value

This shoulder screw is engineered to address common challenges in precision assembly and rotational mechanisms. The 18-8 stainless steel material offers excellent resistance to rust and corrosion, which is critical in moist or chemically exposed settings like packaging machinery, automotive jigs, and conveyor systems. The 1-1/4" shoulder length provides a consistent bearing surface, allowing parts such as gears, pulleys, or linkages to rotate freely without thread contact, thereby reducing wear and maintaining alignment. Combined with the coarse UNC threads and Class 2A thread fit, it ensures quick installation and reliable holding power in soft or brittle materials. The knurled socket head with hex drive enhances grip during tightening, minimizing the risk of stripping and improving torque application in high-vibration environments. This design delivers long-term reliability and ease of maintenance for industrial applications requiring repeated adjustments.

Specification Summary & Compliance

This shoulder screw adheres to UNC coarse thread standards with a Class 2A thread fit for consistent dimensional accuracy. The shoulder diameter is manufactured to a tight tolerance of -0.004" to -0.002", and the shoulder length tolerance is held within -0.005" to 0.005" to ensure precise assembly. It conforms to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environments with strict environmental and safety requirements.