Can any one explain me what is metric system in a easy way??? getting confused in this... does 5M thread means 5mm thread diameter????
thanks in advance
As Mihail pointed out, the 5M designates the nominal outside or inside diameter of the thread. Whether it is outside or inside depends on if you are working with a nut or a bolt. Keep in mind that these are "nominal" dimensions, don't expect a bolt or nut to actually measure 5mm.
In additional to the diameter, the pitch would also be listed. Maybe like M5 x 0.8
The pitch is a measurement of how fine or coarse the threads are. Smaller values are finer.