What are the measurement units of fasteners?

As the most basic measurement index for fastener standard products: measurement units, what basic measurement units do we have? There are two main length measurement units in the world today. One is the metric system, and the measurement units are meters (m), centimeters (cm), millimeters (mm), etc. This type of measurement unit is more commonly used in Southeast Asia such as Europe, my country, and Japan. Many, the other is the British system, the measurement unit is mainly inches (inch), which is equivalent to the market inch of my country's old system, and is used more in the United States, Britain and other European and American countries.

1. Metric system measurement: (decimal system)

1m=100cm=1000mm

1cm

0 1 2 3 4 5 6 7 8 9 10mm

2. Imperial measurement: (octal system)

1 inch=8 cents 1 inch=25.4mm3/8¢¢×25.4 =9.52

1/16 3/16 5/16 7/16 9/16 11/16 13/16 15/16

0 1/8 1/4 3/8 1/2 5/8 3/4 7/8 1 inch

3. Products below 1/4¢¢ are designated by the designation, such as:

4#, 5#, 6#, 7#, 8#, 10#, 12#