S-91247A551 1/4"-20 x 2 1/4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Enhanced load-bearing capacity with Grade 5 strength rating and 120,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through zinc plating that protects against rust and extends service life in harsh environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensuring secure fastening and vibration resistance
• Efficient installation and removal using external hex drive design that provides excellent torque transmission
• Precision manufacturing meeting ASME B18.2.1 standards for consistent quality and dimensional accuracy
• Reduced assembly weight through partial threading while maintaining full strength in critical engagement areas
• Environmental compliance with RoHS 3 and REACH regulations for safe use across global markets

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers exceptional engineering value for industrial assembly applications where vibration resistance and structural integrity are paramount. The zinc plated steel construction provides essential corrosion protection for machinery, equipment frames, and structural components exposed to moderate environmental conditions. The 1/4-20 UNC coarse thread design ensures rapid installation and reliable performance in materials where fine threads might be prone to stripping. With partial threading, this fastener optimizes clamping force distribution while reducing unnecessary weight - particularly valuable in automotive, construction, and manufacturing applications. The combination of Rockwell C25 hardness and precise Class 2A thread fit guarantees consistent performance in high-vibration environments, preventing loosening while maintaining easy disassembly for maintenance operations.

Specification Summary & Compliance

Manufactured to exacting ASME B18.2.1 and SAE J429 standards, this hex head screw features precise Class 2A thread fit tolerances for consistent performance. The 1/4-20 UNC coarse thread maintains proper engagement while the 2-1/4" length with 3/4" minimum thread length ensures sufficient fastening depth. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms environmental responsibility and global market acceptability. Mechanical properties include 120,000 psi tensile strength and Rockwell C25 hardness as specified for Grade 5 fasteners.