S-94688A319 3/8"-16 x 1 1/4" ASME B18.2.1 Square Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance provided by zinc yellow-chromate plating for extended service life in harsh environments
• Precise thread engagement with Unified Standard Class 3A fit ensuring consistent, vibration-resistant connections
• Enhanced torque transmission through external square drive design for secure installation and removal
• Optimized for heavy-duty applications with SAE Grade 8 classification meeting rigorous industrial standards
• Excellent grip in various materials thanks to coarse UNC thread design that resists loosening under stress
• Full threading versatility allowing installation at any point along the fastener's length

Professional Applications & Engineering Value

This high-strength square head screw delivers exceptional engineering value in heavy machinery, construction equipment, and industrial assembly applications where vibration resistance and reliable clamping force are critical. The SAE Grade 8 steel construction combined with 150,000 psi tensile strength ensures these fasteners withstand extreme mechanical stresses without failure. The zinc yellow-chromate plating provides superior corrosion protection in challenging environments, while the external square drive design allows for high-torque installation without cam-out issues. The 3/8"-16 UNC coarse thread configuration offers excellent holding power in both metallic and non-metallic materials, making these square head screws ideal for structural connections, equipment maintenance, and manufacturing applications requiring dependable, long-lasting fastening solutions.

Specification Summary & Compliance

This fastener features precise Unified Standard Class 3A thread fit with 3/8"-16 UNC coarse threading and full threading along the 1 1/4" length. Manufactured to meet ASME B18.2.1 specifications, these square head screws comply with industry standards for dimensional accuracy and performance. The external square drive measures 1/4" in height with a 9/16" head width, providing optimal tool engagement. Constructed from high-strength steel with zinc yellow-chromate plating for corrosion resistance, these fasteners deliver reliable performance in accordance with established industrial fastener requirements.