S-91259A591 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior strength and durability with 140,000 psi tensile strength and 84,000 psi minimum shear strength, ideal for heavy-duty applications.
• Enhanced corrosion resistance provided by the black oxide finish, extending service life in harsh industrial environments.
• Precise alignment and smooth rotation thanks to the knurled head texture and standard shoulder fit, reducing assembly time and wear.
• High thread reliability with Class 3A thread fit and UNC coarse threads, ensuring secure fastening and vibration resistance.
• Consistent hardness and wear resistance from Rockwell C32 hardness, maintaining performance under repeated loads.
• Easy installation and removal using a standard hex drive (5/32"), compatible with common tools for efficient maintenance.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address common industrial challenges such as misalignment, high stress, and corrosion. The 2" shoulder length and precise shoulder diameter tolerance (-0.004" to -0.002") enable accurate positioning in machinery, reducing component wear and improving operational efficiency. With a black oxide finish, it offers enhanced protection against rust in demanding environments like automotive assemblies or heavy equipment. The UNC coarse threads and Class 3A thread fit provide robust, vibration-resistant connections, making it ideal for applications requiring repeated disassembly. Its high tensile and shear strength ensures reliability in industrial fastening where failure is not an option, supported by compliance with ASME B18.3 for consistent quality.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for tight tolerances and UNC coarse threads (1/4"-20) with a thread length of 7/16". The shoulder features a diameter of 5/16" and length of 2" with tolerances of -0.004" to -0.002" and -0.005" to 0.005", respectively, ensuring accurate fits. Manufactured in compliance with ASME B18.3 and material specifications per ASTM A574, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations for environmental safety.