NCCER Millwright Practice Exam 2026 - Free Millwright Practice Questions and Study Guide

The correct answer is split couplings because they are designed to be adjusted and aligned after installation, allowing for precise alignment of the shafts they connect. Split couplings consist of two halves that can be separately adjusted, making it easier to align the shafts accurately once the coupling is mounted. This feature is particularly beneficial when working with equipment that may experience thermal expansions or misalignments over time.

Other types of couplings, such as rigid and fixed couplings, do not allow for adjustment post-installation. Rigid couplings, for instance, provide a solid connection that does not accommodate misalignment, which can lead to stress on the equipment. Flexible couplings are designed to accommodate some degree of misalignment during operation but are typically not aligned after installation in the same manner as split couplings. They allow for minor variances during service rather than requiring realignment once the coupling is in place. Thus, split couplings stand out as the type that can be adjusted and aligned, addressing the need for precise shaft alignment following installation.