What's the Pitch Diameter?

Pitch diameter is the distance from the pitchline to the corresponding pitchline located 180 degrees around. All threads have a pitch diameter whether they are a straight or tapered thread. However, some threads' pitch diameters are actually measured via their crest diameter (diameter from crest to crest) instead.

What is pitch in diameter?

Pitch is the distance from a point on the screw thread to a corresponding point on the next thread measured parallel to the axis. Pitch Diameter is the simple effective diameter of screw thread, approximately halfway between the major and minor diameters.

How do you calculate pitch diameter?

To calculate the pitch diameter, one must imagine a cylinder whose diameter exists at the point where the thread groove width and the thread crest width are both equal to one another and equal to half the nominal pitch of the thread. The diameter of this imagined cylinder is the pitch diameter.