The thread in our UNC thread table belongs to a series of American thread standards that are summarized under the name Unified Thread Standard (UTS). It is mainly used in the USA and Canada, but sometimes also in Australia, Great Britain or Japan. In Germany, you will also come across a UNC thread in special cases, e.g. as a tripod thread or for fastening screws on PC housings. The values in the "UNC thread" table correspond to the specifications of the American National Standards Institute (ANSI), which is responsible for controlling this thread standard. The standard for the UNC thread in the table is ANSI B1.1.
The thread in the UNC thread table can also be referred to as an American coarse thread. It has a flank angle of 60° and can be equated with the ISO metric thread. As you can see from the table for the UNC thread, it is an imperial thread. All dimensions are therefore given in inches.
The designations used in the UNC thread table contain the abbreviation UNC, the outside diameter in inches and an indication of the threads per inch. The thread sizes below 1/4" are an exception. Here you can see from the UNC thread table that the information on the outside diameter is missing. In its place is the English abbreviation No. for Number and a number. These thread sizes are assigned fixed numbers from 1 to 12 in the ANSI standard, which appear after the abbreviation in the "UNC thread" table. The smallest thread size has an outer diameter of 0.073 inches and is referred to as UNC No. 1 - 64. From an outer diameter of 0.25 inches, the numbering system ends in the UNC thread table and an inch is used in the designation instead.
To make your work easier, our table for the UNC thread shows the outside diameter in both inches and mm. This saves you having to do the conversion. We have done the same with the pitch information. In the UNC thread table, you will find the number of threads per inch, which is standard for inch threads. However, we have also listed the pitch P in mm, as you know it from metric threads.