Which alignment method avoids issues like bar sag effectively?

Laser alignment is considered the most effective method for avoiding issues like bar sag because it uses the principles of light to ensure precision measurement. In laser alignment, a laser beam is projected along a predetermined path from one machine to another, allowing for accurate and consistent readings that are not influenced by gravitational pull or physical distortions such as bar sag.

This method significantly enhances the accuracy and reliability of the alignment process, as it provides a clear, straight reference line that can be measured over long distances without the potential errors that mechanical or visual methods might introduce. Laser alignment can identify misalignments that could be missed by other methods and allows for adjustments that are precise and easy to implement. Thus, it is particularly advantageous in circumstances where traditional methods could lead to inaccuracies due to sagging or other geometric distortions of the alignment bars or tools being used.