S-91082A104 ASTM A108, ASTM B633 Inch-to-Metric Female Hex Thread Adapters

Key Features & Benefits at a Glance

• Seamless Inch-to-Metric Conversion – Enables reliable connections between 4-40 (inch) and M3 (metric) threaded components, eliminating compatibility issues in mixed-standard assemblies.
• Exceptional Tensile Strength – Withstands up to 78,000 psi, providing dependable load-bearing capacity and reducing the risk of mechanical failure in demanding applications.
• Superior Hardness & Durability – Rockwell B85 hardness ensures excellent resistance to wear and deformation, extending service life in high-vibration environments.
• Precision Thread Fit – Class 2B (inch) and Class 6H (metric) thread fits guarantee tight, secure fastening with minimal backlash, enhancing assembly accuracy.
• Corrosion-Resistant Coating – Zinc-plated steel construction offers enhanced protection against rust and environmental degradation, suitable for industrial and outdoor use.
• Easy Installation & Removal – External hex drive with 3/16" hex size allows for quick, tool-friendly installation using standard wrenches, improving workflow efficiency.
• Industry Compliance & Reliability – Meets ASTM A108 and ASTM B633 standards, and is RoHS 3 compliant, ensuring material quality and environmental safety.

Professional Applications & Engineering Value

This female hex thread adapter is engineered to solve critical challenges in multi-standard machinery, automotive, and electronics assembly where both inch (4-40) and metric (M3) fasteners are used. Made from zinc-plated steel, it provides robust corrosion resistance and structural integrity, preventing thread stripping and loosening under dynamic loads. The external hex drive design ensures straightforward installation in confined spaces, reducing assembly time and tooling complexity. With a Class 2B/6H thread fit, it maintains precise alignment and torque retention, minimizing rework and downtime in production lines. Ideal for adapting equipment in global supply chains, this adapter enhances interoperability while meeting rigorous ASTM and RoHS requirements for industrial safety and sustainability.

Specification Summary & Compliance

The adapter features inch (4-40) and metric (M3 x 0.5 mm) threads with Class 2B (inch) and Class 6H (metric) thread fit tolerances, ensuring dimensional accuracy and interchangeability. It complies with ASTM A108 (steel bars) and ASTM B633 (zinc plating) specifications, and is RoHS 3 (2015/863/EU) compliant under exemption 6(a)-I for lead as an alloying element in steel, supporting environmental and regulatory standards.