S-90324A106 1/4"-20 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments and reducing maintenance costs.
• Exceptional mechanical strength offering 70,000 psi tensile and 35,000 psi shear strength for reliable performance in high-stress applications.
• Precise Class 3A thread fit ensures tight tolerances and secure fastening, minimizing the risk of loosening under vibration.
• Left-hand UNC coarse thread provides secure engagement in specialized assemblies where reverse threading is required.
• Knurled socket head with 5/32" hex drive allows for easy installation and removal, even in tight spaces, enhancing assembly efficiency.
• Durable Rockwell B55 hardness maintains structural integrity and resists wear over extended use.
• Compliance with RoHS 3 and REACH regulations ensures environmental safety and meets global industry standards for hazardous substances.

Professional Applications & Engineering Value

This 1/4"-20 left hand UNC shoulder screw is engineered to address critical challenges in precision machinery and industrial assemblies. The 18-8 stainless steel material provides excellent corrosion resistance, making it suitable for applications exposed to moisture, chemicals, or outdoor conditions. The left-hand thread direction is specifically designed for components that rotate counter-clockwise, preventing unintended loosening in equipment such as rotating shafts, fixtures, and specialized machinery. The shoulder diameter of 5/16" and length of 3/8" offer precise alignment and act as a pivot or bearing surface, reducing wear on assembled parts. Combined with a Class 3A thread fit and coarse UNC threading, this screw ensures rapid assembly and high clamping force, enhancing operational reliability in automotive, aerospace, and manufacturing sectors where vibration resistance and durability are paramount.

Specification Summary & Compliance

This shoulder screw adheres to UNC thread standards with a Class 3A thread fit for precise dimensional accuracy. The shoulder diameter tolerance is -0.004" to -0.002", and shoulder length tolerance is -0.005" to 0.005", ensuring consistent performance. Manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it meets environmental and safety requirements for industrial use.