VibrAlign and Fixturlaser have done what we can to make the precision shaft alignment process quicker and easier for the end user of our tools. To assist maintenance personnel during an alignment a tolerance table “pops up” on the display unit screen (of our tools) when entering dimensions for the machines being aligned. The tolerances are based on industry standards for typical equipment like pumps and motors.
That does not necessarily mean that these tolerances are appropriate for every alignment or piece of machinery that you maintain. Many machines require tighter alignment tolerances, some others may be more tolerant of additional angular or offset misalignment, or both!
Since tolerances for alignment are based on speed of rotation, I will use that as the reference for comparison.
The point is this, know the alignment tolerance for the machine(s) you are working on. The manufacturer of the machine will give you the proper tolerances for the entire assembly with consideration to all components in a machine, not just the coupling. Coupling manufacturers will give a tolerance for the coupling alone. Be sure you know the shaft alignment tolerance for the machine as a unit.