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.
Definitions of spark plug technical terms. Thread (Diameter) This is the diameter of the plug threads measured across the thread as pictured. Standard pitches for various thread diameters are listed below but it is by no means guaranteed that a standard diameter thread will use a standard pitch size.