S-91309A844 3/4"-10 x 2 1/4" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating that protects against rust and extends service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable load-bearing capacity and prevents failure under stress
• Class 2A thread fit provides smooth assembly and consistent engagement for faster installation and reduced cross-threading risks
• Fully threaded design offers maximum grip and uniform clamping force along the entire length for secure fastening
• External hex drive with 1 1/8" head width allows for high-torque application using standard tools, improving installation efficiency
• Coarse UNC threads enable quick assembly and better performance in materials prone to stripping or vibration
• Rockwell B69 hardness delivers excellent durability and resistance to wear in repetitive or high-stress applications

Professional Applications & Engineering Value

This 3/4"-10 UNC hex head screw is engineered to address critical fastening challenges in industrial settings where vibration, heavy loads, and environmental exposure are common. The high-strength steel construction combined with zinc plating provides a robust barrier against corrosion, making it ideal for outdoor machinery, structural assemblies, and manufacturing equipment. The coarse thread design ensures rapid installation and maintains holding power in softer materials or where debris accumulation is a concern. With its external hex drive and fully threaded body, it offers consistent torque transmission and full-length engagement, reducing the risk of joint loosening under dynamic loads. These features make it a reliable choice for construction, automotive, and heavy equipment applications requiring ASME B18.2.1 compliant fasteners that meet rigorous performance standards.

Specification Summary & Compliance

This hex head screw features precision UNC coarse threads with Class 2A thread fit for consistent dimensional accuracy and ease of assembly. It is manufactured in accordance with ASME B18.2.1 specifications where identified under ASTM A307, ensuring reliable mechanical properties and interchangeability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming adherence to environmental and safety standards for hazardous substance restrictions.