If you can only take three readings around the 360-degree arc, what should you do to perform the alignment?

When performing alignments, particularly when limited to three readings around a 360-degree arc, it is essential to ensure that the alignment process is as accurate as possible. Balancing the vertical readings with the horizontal is a fundamental approach in this scenario because it helps in compensating for any discrepancies that may arise due to having fewer readings.

In essence, by taking readings from both vertical and horizontal perspectives and ensuring they are balanced against one another, the millwright can establish a more complete understanding of the machinery's alignment. This method addresses the potential inaccuracies that can emerge from having an incomplete data set and aids in achieving the best possible alignment with the available information. Balancing the readings is particularly important because it can help to mitigate any variances caused by positional errors or other alignment issues that could skew the readings in the absence of a fourth point.