The thread of the 16-UN thread table belongs to the Unified National Fixed Pitch Series (UN), which in turn is part of the Unified National Thread Series (UTS). This is a series of American thread standards that are defined and monitored by the American National Standards Institute (ANSI). The values in the 16-UN thread table are based on the ANSI B1.1 standard. As you can see from the 16-UN thread table, the special feature of the UN series is the unchanging number of threads per inch. This means that all thread sizes have the same number of threads, in the case of the 16-UN threads in the table there are 16 threads. The UN series also includes threads with 4, 6, 8, 20, 28 and 32 gears per inch.
The 16-UN thread is an imperial thread with a 60° flank angle. As with all UN threads, the 16-UN thread table only covers those combinations of outside diameter and pitch per inch that are not already available in other thread standards such as UNC, UNF or UNEF. The 16-UN thread table therefore only contains special pitches for special applications. It is also noticeable that there are significantly fewer thread sizes in the 16-UN thread table than in the standards for other UTS threads. Due to the fixed number of threads per inch, not every combination of pitch and outside diameter makes sense. Only those variants that prove to be practicable in use have been included in the 16-UN thread table.
The table for the 16-UN thread only contains thread sizes from an outside diameter of 1". The thread designation is made up of the outside diameter and the abbreviation 16-UN. In contrast to other UTS threads, the number of threads per inch no longer needs to be added to the thread designation in the 16-UN thread table, as this is fixed at 16. In our 16-UN thread table, we have listed the outer diameter in mm in addition to the information in inches if you want to work with metric data. In the 16-UN thread table you will also find the conversion of the number of threads per inch into mm, which in this case corresponds to 1.587 mm.