S-91247A018 1/4"-28 x 2 1/4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior tensile strength of 120,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Enhanced corrosion resistance from zinc plating extends service life in harsh industrial environments, minimizing maintenance needs.
• Precise Class 2A thread fit with UNF fine threads provides secure, vibration-resistant connections for critical assemblies.
• Grade 5 steel construction with Rockwell C25 hardness offers excellent durability and wear resistance under heavy loads.
• External hex drive design allows for easy installation and removal with standard tools, improving assembly efficiency.
• Partial threading enables optimal grip and clamping force control in a variety of material thicknesses.
• Compliance with ASME B18.2.1 and environmental standards ensures consistent quality and regulatory adherence for industrial use.

Professional Applications & Engineering Value

This Grade 5 steel hex head screw is engineered to address common industrial fastening challenges, such as joint integrity under dynamic loads and environmental exposure. The zinc-plated finish provides a protective barrier against moisture and chemicals, making it ideal for outdoor machinery, automotive assemblies, and construction equipment. With its UNF fine thread and Class 2A fit, it delivers precise engagement in metal-to-metal applications, reducing the likelihood of loosening due to vibration. The partial threading design allows for effective clamping in varying material depths, ensuring stable connections in structural frameworks and heavy-duty manufacturing. By meeting ASME B18.2.1 standards, it guarantees dimensional accuracy and reliability, supporting efficient maintenance and long-term performance in demanding sectors like aerospace, energy, and transportation.

Specification Summary & Compliance

This fastener adheres to Class 2A thread fit tolerances and UNF fine thread standards, ensuring precise dimensional accuracy as per ASME B18.2.1 specifications. It is manufactured from Grade 5 steel with a tensile strength of 120,000 psi and Rockwell C25 hardness. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), confirming it is free from restricted substances and suitable for global industrial use.