S-90303A137 1/4"-20 x 1 1/4" ASME B18.3, ASTM A574 Nylon-Tip Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional Strength & Durability: With 180,000 psi tensile strength and Rockwell C39 hardness, this screw withstands high-stress applications without failure.
• Non-Marring Surface Protection: The integrated nylon tip prevents damage to contact surfaces, ideal for finished assemblies and delicate materials.
• High-Temperature & Chemical Resistance: Black-oxide coating on alloy steel provides corrosion resistance, while the nylon tip operates reliably from -50° to 250°F.
• Precision Thread Engagement: Class 3A thread fit ensures tight, secure fastening with minimal backlash in demanding mechanical systems.
• Easy Installation with Standard Tools: Hex socket drive (3/16") allows for high-torque application using common Allen wrenches.
• Full Thread Engagement: Fully threaded design provides consistent clamping force along the entire 1-1/4" length.
• Industry Standard Compliance: Manufactured to ASME B18.3 specifications for guaranteed interchangeability and performance.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw delivers critical performance advantages in precision assembly applications where surface protection and reliable fastening are paramount. The non-marring nylon tip eliminates scratching and damage to finished surfaces while maintaining secure fastening in temperature-sensitive environments from -50° to 250°F. Engineered with Class 3A UNC coarse threads, the fastener provides superior thread engagement and vibration resistance in machinery, automotive, and industrial equipment assemblies. The hex socket drive enables high-torque installation in confined spaces, while the fully threaded design ensures uniform stress distribution. These features make it ideal for applications requiring repeated disassembly and reassembly without compromising performance or surface integrity.

Specification Summary & Compliance

This socket head cap screw features precision 1/4"-20 UNC coarse threads with Class 3A thread fit for superior dimensional accuracy. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, it ensures consistent performance and interchangeability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications requiring strict material compliance standards.