How can dial indicator sag be corrected?

To correct dial indicator sag, resetting the dial at a 12 o'clock position is essential because it allows for accurate readings by ensuring that the indicator is aligned with the vertical reference point. When a dial indicator is sagging, it results in erroneous measurements as it may be tilted or not in line with the object being measured. By resetting it to the 12 o'clock position, the indicator compensates for any sag, allowing for precise tracking of movement and alignment. This practice helps in setting a baseline reference for accurate measurements, which is critical in the alignment process.

Other methods, such as lowering the dial to touch the ground or increasing the weight of the setup, do not address the issue of sag effectively and may lead to further inaccuracies. Calibrating the dial indicator before use is important for ensuring that it is functioning correctly, but it does not specifically rectify the sag itself. Therefore, resetting the dial at the proper orientation is the most effective way to correct for sag and maintain measurement integrity.