S-91465A119 5/16"-18 x 1 1/4" ASTM A307 Square Head Screws

Key Features & Benefits at a Glance

• Superior torque transmission through external square drive design for reliable installation in high-vibration environments
• Excellent corrosion resistance with ASTM A307 Grade A steel construction ensuring long-term durability
• Optimized holding power with fully threaded 5/16"-18 UNC coarse thread pattern for maximum grip strength
• Precise thread engagement with Unified Standard Class 2A fit for consistent performance across applications
• Environmental compliance assurance with RoHS 3 (2015/863/EU) compliance for regulated industrial settings
• Reliable mechanical properties with 60,000 psi tensile strength and Rockwell B69 hardness for demanding applications
• Easy identification and installation with standardized 1/2" head width and 13/64" head height dimensions

Professional Applications & Engineering Value

This 5/16"-18 UNC square head screw delivers exceptional engineering value in industrial fastening applications where reliability is paramount. The ASTM A307 Grade A steel construction provides the ideal balance of strength and machinability, while the coarse thread design ensures rapid installation and superior resistance to vibration loosening. The fully threaded configuration maximizes engagement surface area, distributing stress evenly across the entire fastener length. This makes it particularly valuable in construction, machinery assembly, and structural applications where right-hand threading and external square drive compatibility are essential for maintenance accessibility and torque efficiency. The combination of 60,000 psi tensile strength and standardized dimensions ensures predictable performance in heavy-duty fastening scenarios.

Specification Summary & Compliance

This square head screw maintains Unified Standard Class 2A thread tolerances with precise 5/16"-18 UNC coarse thread specifications. Manufactured to ASTM A307 standards, the fastener demonstrates compliance with RoHS 3 (2015/863/EU) environmental regulations. The dimensional accuracy includes consistent 1-1/4" length, 0.3125" thread diameter, and standardized head dimensions (13/64" height, 1/2" width) ensuring compatibility with standard square drive tools and predictable performance across industrial applications.