What is Thread Allowance (es)?
Thread allowance (es) is the distance in maximum material condition between the nominal thread diameter and the crest of an external thread.
The allowance is defined in the standards for each class of each thread. It serves as an indication of how tight or lose the thread is.
\( \large es = \frac {\left ( \text{Nominal Thread Diameter}\,-\,\text{Max Allowed Major Diameter}\right )}{2} \)
A tight thread provides better accuracy but is harder to assemble. A loose thread is easier to assemble but provides lower accuracy.
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