Introduction to shaft alignment 
Shaft alignment is the act of measuring the relative position of two machines that are coupled and repositioning them so that the rotational axes of the two shafts form a straight line (collinear) when the machines are at normal operating temperatures.
In industry after industry, critical machines in the production process require precise alignment to perform to specs. If machine misalignment occurs, valuable production time can be lost.
Nearly 50% of all breakdowns in rotating machines occur due to machine misalignment. During these breakdowns, 100% of production is lost. So an investment in machine alignment – whether in better tools, better practices or better knowledge – can be justified in uptime increases, and make payback time short.
View the video about alignment concpets below for an understanding what shaft alignment is about