JIS B 1181​ Hexagon Nut

The JIS B 1181 nut is a Japanese Industrial Standard specification that defines the dimensions, materials, and mechanical properties for hexagon nuts used in general-purpose fastening applications across a wide range of industries. This comprehensive standard, officially titled"Hexagon Nuts,"covers multiple nut styles including hexagon nuts, hexagon thin nuts, and hexagon slotted nuts, providing a complete framework for metric fasteners in the Japanese market. Manufacturers producing these nuts must comply with rigorous quality control requirements, including thread gauging and mechanical testing, to ensure reliable and consistent product quality.

The Japanese standard hex nut is characterized by its precise metric dimensions, with thread sizes ranging from M1.6 to M64, and is manufactured in property classes from 4 to 12, matching corresponding bolt grades such as 4.6, 8.8, 10.9, and 12.9. These nuts feature a classic six-sided design that allows easy tightening with standard wrenches, and they are widely used in automotive manufacturing, industrial machinery, electronics, construction equipment, and general assembly applications. The JIS B 1181 standard ensures interchangeability with other metric fasteners, facilitating international trade and global supply chain integration.

As a metric hex nut JIS, it is available in a variety of surface finishes including plain (uncoated), zinc-plated, black oxide, hot-dip galvanized, and yellow chromate, providing options for different environmental conditions and corrosion resistance requirements. The nuts are typically manufactured from carbon steel, alloy steel, or stainless steel, with dimensional tolerances specified to ensure proper fit with corresponding bolts. JIS B 1181 is widely recognized as the primary hex nut standard in Japan and is also commonly used in other Asian markets, making it an essential fastener for engineers and procurement professionals seeking reliable metric nut solutions.