S-91327A148 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch ensures secure fastening in high-stress environments, maintaining integrity from -50° to 250°F.
• Exceptional corrosion resistance from 18-8 stainless steel and passivated finish, ideal for harsh industrial conditions and extended service life.
• High tensile strength of 70,000 psi and Rockwell B55 hardness provide reliable load-bearing capacity and durability against wear.
• Precision Class 3A thread fit guarantees tight tolerances and smooth assembly, reducing the risk of cross-threading and improving efficiency.
• Knurled socket head design offers enhanced grip for easy installation and removal, even in confined spaces with a standard hex drive.
• Stable shoulder alignment with a 5/16" diameter and 1 1/2" length ensures precise component positioning and reduced wobble in assemblies.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental responsibility for global applications.

Professional Applications & Engineering Value

This 1/4"-20 UNC shoulder screw is engineered to address common industrial challenges such as component misalignment and vibration-induced loosening in machinery. Made from 18-8 stainless steel with a passivated finish, it resists corrosion in demanding environments like automotive assemblies or outdoor equipment. The integrated nylon patch thread locker provides a permanent locking mechanism, eliminating the need for additional adhesives and reducing maintenance downtime. With a Class 3A thread fit and precise shoulder dimensions, it ensures accurate alignment in pivots, gears, and rotating parts, enhancing overall system reliability. Ideal for applications requiring high tensile strength and vibration resistance, this screw supports efficient production and long-term performance in sectors such as aerospace, manufacturing, and electronics.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 specifications, with a Class 3A thread fit for superior dimensional accuracy in UNC coarse threads. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring it is free from hazardous substances. The manufacturing process maintains tight tolerances, including a shoulder diameter of 5/16" with a tolerance of -0.004" to -0.002" and a shoulder length of 1 1/2" with a tolerance of -0.005" to 0.005", guaranteeing consistent performance in industrial fastening applications.