NCCER Millwright Practice Exam

When setting up dial indicators, the contact point pressure should be sufficient so that the stem is at what point in its travel range?

1. At the end of its travel range

2. At the midpoint of its travel range

3. Near the beginning of its travel range

4. Exceeding its travel range

The correct answer is: At the midpoint of its travel range

When setting up dial indicators, it is crucial for the contact point pressure to be sufficient so that the stem is positioned at the midpoint of its travel range. This is important because positioning the stem at the midpoint allows for accurate measurements, as it optimizes the sensitivity and responsiveness of the indicator throughout its operational range. When the stem is near the midpoint, it reduces the likelihood of hitting its maximum or minimum limits, which can lead to instrument damage or inaccuracies in measurement. In contrast, having the stem at the extremes of its travel range can lead to excessive load on the mechanism, potentially causing wear, sticking, or even malfunction. Therefore, ensuring that the contact point pressure is set correctly to achieve a midpoint position is key for the effective use of dial indicators in precision measurements.