What is the Length of Engagement of a Thread?
š¹A shot video with a clear explanation of the thread term "Length of Engagement". Length of Engagement (LE) is the axial distance of full (360Ā°) threads in contact between the male and female parts of a threading assembly. It is usually measured in multiples of the pitch. For example, 5P means a length of engagement of five times the pitch. š¹ Unified Inch Threads per ASME B1.1: The values listed in the charts for UNC/UNF are valid between 5P (five times the pitch) to 1.5D (1.5 times the nominal diameter) engagement length. However, the standard provides formulas that take it into account. If your length of engagement is outside of this range, you should make manual calculations. š¹ Metric Threads according to ISO 965: The standard divides the length of engagement into 3 groups. Normal, Short, and Long (designates N, S & L). It provides charts and formulas to determine the LE range for each diameter and pitch combination. Following that, it recommends which classes to use for each LE range. However, the designer of a part may choose a class combination outside of this list. Additional Resources: š https://www.machiningdoctor.com/glossary/length-of-engagement-le/ š https://www.machiningdoctor.com/calculators/threading/