S-90324A128 5/16"-18 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh industrial environments.
• Superior thread engagement and vibration resistance due to the left-hand UNC coarse thread and precise Class 3A fit.
• High mechanical strength and durability, offering a tensile strength of 70,000 psi and a minimum shear strength of 35,000 psi for reliable performance.
• Secure and non-slip installation enabled by the knurled socket head and hex drive, preventing tool slippage.
• Accurate component alignment and spacing with a precisely machined 3/8" shoulder diameter and 1/2" shoulder length.
• Compliance with major environmental regulations, being RoHS 3 and REACH compliant for safe and responsible use.
• Consistent Rockwell B55 hardness ensures long-term wear resistance and dimensional stability.

Professional Applications & Engineering Value

This left-hand thread shoulder screw is engineered to address critical assembly challenges in demanding applications. The 18-8 Stainless Steel material provides excellent corrosion resistance, making it suitable for machinery, automotive, and marine components exposed to moisture and chemicals. The 5/16"-18 UNC coarse thread in a left-hand direction is specifically designed for applications where standard right-hand threads may loosen under counter-rotational forces, enhancing safety in rotating assemblies. The precision shoulder with a 3/8" diameter and 1/2" length acts as a pivot, bearing surface, or spacer, ensuring accurate alignment of parts and reducing wear. Combined with a knurled socket head for secure driving, this fastener prevents assembly errors and improves operational reliability in high-stress environments.

Specification Summary & Compliance

This shoulder screw adheres to UNC coarse thread standards with a Class 3A fit for high precision. The shoulder diameter is manufactured to a tight tolerance of -0.004" to -0.002", and the shoulder length to -0.005" to 0.005", ensuring consistent performance. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for environmentally conscious industrial applications.