S-90298A645 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments.
• Precise component alignment ensured by the 6" shoulder with tight length tolerance (±0.005") and standard shoulder fit.
• High-strength performance delivering 70,000 psi tensile strength and 35,000 psi minimum shear strength for demanding applications.
• Secure, non-slip installation provided by the knurled socket head and hex drive, preventing tool slippage.
• Reliable thread engagement with Class 3A fit and coarse UNC threads for quick assembly and vibration resistance.
• Compliance with industry standards including ASME B18.3, ensuring consistent quality and interchangeability.
• Environmental and safety compliance with RoHS 3 and REACH regulations, suitable for regulated industries.

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to address critical alignment and durability challenges in industrial machinery, automation systems, and precision equipment. The 18-8 stainless steel material offers excellent corrosion resistance, reducing maintenance in humid or corrosive settings. The 6" shoulder length with minimal tolerance variations ensures precise positioning of moving parts, such as in bearings, pulleys, or linkages, minimizing wear and misalignment. The Class 3A thread fit and coarse UNC thread provide robust, vibration-resistant connections, essential for high-stress applications. With a Rockwell B55 hardness and high tensile strength, this socket head shoulder screw maintains integrity under heavy loads, making it a reliable choice for assembly lines, robotics, and heavy-duty equipment where performance and longevity are paramount.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC thread with Class 3A fit for precise thread engagement. The shoulder diameter is 3/8" with a tolerance of -0.004" to -0.002", and the shoulder length is 6" with a tolerance of -0.005" to 0.005", ensuring high dimensional accuracy. Manufactured in compliance with ASME B18.3 specifications, it also meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, confirming its suitability for environmentally conscious and regulated industrial applications.