S-91286A149 1/4"-28 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength and Grade 8 classification, ensuring reliable performance in high-stress applications.
• Superior corrosion resistance provided by the zinc-flake coating, extending service life in harsh industrial environments.
• Secure and precise fastening due to the Class 2A thread fit and UNF fine threading, minimizing the risk of loosening under vibration.
• Optimized for high-torque installation with an external hex drive and robust hex head design, allowing for easy and efficient assembly.
• Enhanced durability and wear resistance from Rockwell C33 hardness, maintaining fastener integrity over repeated use.
• Versatile partial threading enables secure clamping on a wide range of material thicknesses without compromising strength.
• Compliance with major industry standards including ASME B18.2.1 and SAE J429, ensuring consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy machinery, automotive, and construction sectors where high tensile strength and corrosion resistance are paramount. The zinc-flake coated steel construction provides long-lasting protection against rust and chemical exposure, reducing maintenance costs and downtime. Its 1/4"-28 UNF fine threading and Class 2A thread fit ensure tight, reliable connections that resist loosening under dynamic loads and vibrations. The partially threaded design allows for precise clamping force distribution, making it ideal for assemblies requiring both strong grip and adjustability. By meeting ASME B18.2.1 and SAE J429 specifications, this fastener delivers consistent performance and safety in demanding industrial applications, from structural frames to engine components.

Specification Summary & Compliance

This screw features precise Class 2A thread fit and UNF fine threading per industry standards, ensuring dimensional accuracy and reliable engagement. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, guaranteeing consistent quality and performance. Additionally, the product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to environmental and safety regulations for hazardous substances.