3 4 16unf意思

"3 4 16UNF" is a thread designation for a Unified National Fine thread. Here's what each number means:

  1. "3" refers to the number of threads per inch (TPI). This means that for every inch of length, there are three threads.

  2. "4" is the major diameter of the thread in sixteenths of an inch. In this case, the major diameter is 4/16 inches, which equals 1/4 inch.

  3. "16" stands for the series of the thread. In this context, "UNF" means Unified National Fine, and the "16" is part of the designation for the thread series, which is determined by the pitch and the major diameter.

So, a 3-4-16UNF thread is a fine-pitch thread with a major diameter of 1/4 inch and three threads per inch. This type of thread is commonly used in fasteners like bolts and screws.