Before revision: For a bolt with a given thread per inch, on one end and a second thread per inch, on the other, the change in distance (or ), and the effective thread per inch , is calculated by: For example, a bolt with coarse threads (16 tpi, per turn) on one end and fine threads (24 tpi, per turn) on the other changes the distance between the nuts by about per revolution and is equivalent to a 48 tpi (0.53 mm/thread) thread:
After revision: For single start Metric threads, the effective pitch is simply the difference between the two thread pitches:For example, an M5x0.80 thread paired with an M4x0.70 thread will produce a differential motion of 0.1 mm, or 100 microns per revolution.For a bolt with a given thread per inch, on one end and a second thread per inch, on the other, the change in distance (or ), and the effective thread per inch , is calculated by: For example, a bolt with coarse threads (16 tpi, per turn) on one end and fine threads (24 tpi, per turn) on the other changes the distance between the nuts by about per revolution and is equivalent to a 48 tpi (0.53 mm/thread) thread: