Wherever there is milkweed there will be Monarch butterflies. The monarch is widely distributed across North America, from Central America northwards to southern Canada, and from the Atlantic to the Pacific coasts.
The pitch diameter (often called the effective diameter) of a parallel thread is the diameter of the imaginary co-axial cylinder which intersects the surface of the thread in such a manner that the intercept on a generator of the cylinder, between the points where it meets the opposite flanks of a thread groove, is equal to half the nominal pitch of the thread.
For Over 150 Years, The Standard of Accuracy. Calibrating external thread pitch diameter with three thread wires is a well-proven method and the most common one in use. Although any size wire between the minimum wire size and the maximum wire size may be used, common practice is to use the best wire size. This is the size that contacts the thread at the pitch diameter thus eliminating thread angle variation errors. 2. 3. For maximum accuracy, thread wire tolerances are very tight.