 Welcome back MechanicalEI, did you know that thread designations drastically help reduce drawing times and make up for a much clearer depiction of an engineering drawing? This makes us wonder, what is thread designation? Before we jump in, check out the previous part of this series to learn about what machine elements are. Now, thread designation is an M number indicating the major diameter of the thread followed by the pitch measured in millimeters per thread. For example, an M22 x 1.5 screw has a nominal outer diameter of 22 millimeters and each thread is 1.5 millimeters thick. Based on their forms, threads are classified as first isometric thread which is used for all general purposes, second square threads which is ideal thread for power transmission, third ACME thread which is stronger than square thread and finally buttress thread which is designed to handle heavy forces in a single direction. When the drawing of a component in its true projection involves a lot of time, its convention may be used to represent the actual component. Shown here are the conventional representations of three common types of gears namely, spur gear, bevel gear, worm wheel and its worm. Even engineering materials due to their complexity are assigned certain designations so as to ease their representation in an engineering drawing. Given here are some of the common engineering materials and their representations. Hence, we first saw what thread designation is and then went on to see how machine components and materials are conventionally represented. So like, subscribe and comment with your feedback to help us make better videos. Thanks for watching. Also, thanks a lot for those constructive comments. You helped the channel grow. So here are the top mechanical EIs of our last videos. In the next episode of Mechanical EI, find out what limits, fits and tolerances are.