TPI

TPI stands for threads per inch. TPI refers to the number of threads that are within an inch of length on a screw, bolt, or fastener. Often compared to thread pitch, the TPI of a part is typically used when defining the measurements of the part and can be calculated from the thread pitch if necessary. When the thread itself is finer, the screw will have a higher TPI and when the thread itself is courser, the part will have a lower TPI.