S-93310A337 1/4"-20 x 1 1/4" ASME B18.3, ASTM F879, MIL-DTL-18240 Thread-Locking Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch that maintains secure fastening from -70° to 250° F, preventing loosening in dynamic environments.
• Superior corrosion resistance from 18-8 stainless steel construction, ensuring long-term durability in harsh industrial conditions.
• High tensile strength of 70,000 psi and Rockwell B55 hardness for reliable performance under heavy loads and stress.
• Precise Class 3A thread fit with UNC coarse threading for easy installation and consistent engagement in various materials.
• Secure hex drive (5/32") and rounded button head design for efficient torque application and a flush, low-profile finish.
• Full threading along the 1-1/4" length maximizes grip and adjustability in assemblies requiring deep engagement.
• Compliance with major standards including ASME B18.3, MIL-DTL-18240, and ASTM F879, ensuring quality and interoperability.

Professional Applications & Engineering Value

This 1/4"-20 nylon patch lock screw is engineered to address critical challenges in industrial fastening, such as vibration-induced failure and corrosion. The 18-8 stainless steel material provides excellent resistance to rust and chemicals, making it ideal for machinery, automotive, and outdoor equipment. The permanent nylon patch locking feature eliminates the need for additional lock washers or adhesives, reducing assembly time and enhancing reliability in high-vibration applications like motors and conveyors. With a coarse UNC thread and Class 3A fit, it ensures quick, secure installation in metals and plastics, while the rounded head and hex drive offer a clean appearance and easy access in confined spaces. This screw delivers consistent performance where safety and longevity are paramount.

Specification Summary & Compliance

This fastener features a 1/4"-20 UNC coarse thread with Class 3A precision fit for tight tolerances and reliable engagement. It is manufactured in compliance with ASME B18.3, MIL-DTL-18240, and ASTM F879 specifications, ensuring adherence to industry standards for dimensions and performance. The product is also certified RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for hazardous substances.