S-91375A548 1/4"-20 x 1 3/4" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Exceptional holding power with Class 3A UNC coarse threads for reliable, vibration-resistant fastening in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in various industrial environments.
• High-strength durability with a Rockwell C45 hardness rating, ensuring the screw withstands high stress without stripping or deforming.
• Secure and easy installation using a standard 1/8" hex key, providing a flush, headless profile for space-constrained assemblies.
• Positive gripping action from the cup tip design, which bites into the contact surface to prevent component slippage.
• Broad industrial compatibility due to compliance with ASME B18.3, RoHS 3, and REACH standards, ensuring safety and regulatory adherence.
• Optimized for right-hand thread applications, making it ideal for standard assembly processes and quick replacements.

Professional Applications & Engineering Value

This black-oxide alloy steel set screw is engineered to address critical challenges in machinery, automotive, and equipment manufacturing where vibration resistance and long-term reliability are paramount. The Class 3A UNC coarse thread provides a tighter fit and superior clamping force compared to standard threads, reducing the risk of loosening under dynamic loads. The headless hex drive design allows for flush mounting in confined spaces, while the cup tip ensures a firm grip on shafts, collars, and pulleys. Manufactured from high-strength alloy steel and treated with a protective black-oxide finish, it resists rust and wear, making it a dependable choice for heavy-duty industrial fastening applications that demand consistent performance and compliance with international standards.

Specification Summary & Compliance

This set screw features a 1/4"-20 UNC coarse thread with a Class 3A thread fit for high precision and strength. It meets ASME B18.3 specifications for dimensional accuracy and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for use in various industrial and commercial environments.