S-91257A411 1/4"-20 x 7" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating that extends service life in harsh environments
• Optimized torque transmission through the external hex drive design for secure installation and removal
• Enhanced mechanical durability with Rockwell C33 hardness that maintains structural integrity under repeated stress
• Precise thread engagement with Class 2A UNC coarse threading that ensures consistent fastening in industrial assemblies
• Partial threading design that allows for both secure clamping and adjustment flexibility in various mounting scenarios
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed quality and interchangeability

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for industrial applications where mechanical reliability cannot be compromised. The zinc yellow-chromate plated steel construction provides exceptional corrosion resistance in demanding environments, while the 150,000 psi tensile strength ensures structural integrity in heavy machinery, construction equipment, and automotive assemblies. The UNC coarse threading with Class 2A tolerance enables rapid installation and secure fastening in steel frameworks and structural connections. The 7-inch length with partial threading offers versatility for applications requiring both clamping force and adjustment capability, making these industrial fasteners ideal for critical joints in manufacturing, infrastructure, and mechanical systems where vibration resistance and long-term performance are paramount.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with 1/4"-20 UNC coarse threads and Class 2A thread fit for consistent engagement. These hex head screws comply with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and mechanical performance. The Grade 8 classification guarantees minimum tensile strength of 150,000 psi and Rockwell C33 hardness, while the zinc yellow-chromate plating provides corrosion protection meeting industry standards for industrial fastener applications.