S-90324A012 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh industrial environments.
• Exceptional thread reliability due to Class 3A fit and UNC coarse thread spacing, ensuring secure, vibration-resistant connections.
• Enhanced grip and tool engagement from the knurled hex socket head, preventing slippage during installation.
• High mechanical strength with 70,000 psi tensile and 35,000 psi minimum shear strength for demanding applications.
• Precise shoulder alignment with tight diameter and length tolerances, providing accurate component positioning.
• Left-hand thread functionality for specialized assemblies requiring reverse threading to prevent loosening.
• Regulatory compliance assurance with RoHS 3 and REACH, meeting international environmental and safety standards.

Professional Applications & Engineering Value

This 4-40 UNC left-hand thread shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and rotational equipment. The 18-8 Stainless Steel material offers excellent resistance to rust and oxidation, extending service life in humid or corrosive settings. Its Class 3A thread fit and coarse UNC thread provide superior holding power against vibrations, while the left-hand thread direction is specifically designed for applications where standard right-hand threads may unintentionally loosen due to rotational forces. The knurled hex socket head ensures secure tool engagement, reducing the risk of stripping during high-torque assembly. Combined with a precisely machined shoulder for accurate alignment, this screw delivers reliable performance in industrial shoulder screw applications such as pivots, guides, and spacers.

Specification Summary & Compliance

This shoulder screw adheres to UNC thread standards with a Class 3A thread fit for high precision. Shoulder dimensions include a diameter of 1/8" (tolerance: -0.004" to -0.002") and length of 1/4" (tolerance: -0.005" to 0.005"), ensuring consistent alignment. It is manufactured to meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, guaranteeing environmental safety and regulatory adherence for global industrial use.