S-91257A687 7/16"-14 x 4 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress industrial applications, reducing fastener failure risks.
• Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh environments, minimizing maintenance needs.
• High hardness rating (Rockwell C33) provides excellent wear resistance, maintaining thread integrity through repeated use.
• Precise Class 2A thread fit with UNC coarse threading enables easier installation and better vibration resistance in heavy machinery.
• Partially threaded design allows for optimal clamping force distribution, preventing joint loosening in structural applications.
• External hex drive compatibility with standard tools simplifies installation and removal, saving valuable maintenance time.
• Grade 8 certification guarantees consistent quality and performance meeting rigorous industrial standards.

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions where high tensile strength and corrosion resistance are paramount. The 7/16"-14 UNC coarse thread configuration provides superior holding power in structural steel connections, heavy equipment assembly, and machinery fabrication. The zinc yellow-chromate plating creates a protective barrier against oxidation and chemical exposure, making these fasteners ideal for outdoor applications, manufacturing plants, and automotive systems. With partial threading concentrating clamping force where needed most, these screws prevent material distortion while maintaining joint integrity under extreme vibration and dynamic loads. The external hex drive design ensures compatibility with standard industrial tools, streamlining installation in confined spaces and high-volume production environments.

Specification Summary & Compliance

Manufactured to exacting Class 2A thread fit tolerances with UNC coarse threading (7/16"-14) in the inch measurement system. These hex head screws comply with ASME B18.2.1 dimensional specifications and SAE J429 Grade 8 mechanical properties. Fully compliant with RoHS 3 (2015/863/EU) restrictions and REACH (EC 1907/2006) regulations regarding hazardous substances. The 4 1/2" length with 1 1/8" minimum thread length provides consistent engagement across various material thicknesses.