NCCER Millwright Practice Exam

When setting up an angle iron jig, where should the second indicator be positioned?

1. At the base of the jig

2. At the end of the workpiece

3. At the exact bottom of the driven shaft

4. Alongside the first indicator

The correct answer is: At the exact bottom of the driven shaft

The second indicator should be positioned at the exact bottom of the driven shaft when setting up an angle iron jig. This placement is crucial for ensuring accurate alignment and measurement throughout the setup process. By positioning the second indicator at the driven shaft's bottom, you create a reference point that allows for precise adjustments and ensures that the jig is properly aligned with the rotational axis of the driven components. This can significantly influence the functionality and safety of the machine being constructed or serviced. While other placements might seem logical, they do not provide the same level of precision or reliability. For instance, positioning it at the base of the jig or at the end of the workpiece may introduce variances due to the physical tolerances or imperfections present in those areas. The objective is to ensure that all components are correctly aligned, preventing operational issues and ensuring that the result meets the design specifications. Therefore, placing the second indicator alongside the first indicator may be helpful for additional verification, but it does not directly provide the measurements needed from the driven shaft's perspective.