Thread Pitch
Glossary · Threads & Fits
At a glance
- Category /
- Threads & Fits
- Also called /
- TPI, threads per inch
- Related /
- 3 terms
- Source /
- Written in the shop
Thread pitch describes how far apart the threads are — stated in inch practice as threads per inch (TPI) and in metric as the distance in millimetres between adjacent crests.
Also called: TPI · threads per inch
In practice
A 1/2-13 bolt has 13 threads per inch; an M12 x 1.75 has 1.75 mm between threads. Coarse and fine series exist for most diameters.
Why it matters
Diameter alone does not identify a thread. Two bolts of the same diameter with different pitches will start and then bind, and forcing one is how a good part gets a damaged thread.
More in Threads & Fits
Have a drawing with this on it?
Request a Quote
Send it over and we will tell you what it will take to hold — and what is safe to loosen.