What is an indicator used for in machining?

An indicator is a precision measuring device that is essential for ensuring the accuracy of a workpiece in machining processes. It is primarily used to gauge the dimensions and geometrical features of a part, verifying that it meets the specified tolerances. This is crucial, as even slight deviations from the intended specifications can lead to improper fit, function, or performance of the final product.

Indicators work by providing a visual readout of movement or displacement, allowing the machinist to detect any errors in alignment, flatness, or roundness. By using indicators, machinists can set up their machines accurately, adjusting the setup until the measurements fall within the desired range. This contributes significantly to quality control and maintains the integrity of the machining process.

In contrast, the other options involve functions that are not the primary purpose of an indicator. For example, lighting up the workspace improves visibility but does not measure precision. Enhancing visibility of the cutting tool pertains to safety and ease of operation rather than measurement. Marking points on a workpiece can be done with other tools, but is not the function of an indicator. Thus, the role of an indicator is crucial for maintaining accuracy and ensuring that machined parts adhere to the required specifications.