What is a key factor in choosing a measuring instrument for dimension checking?

The choice of measuring instrument for dimension checking is significantly influenced by the tolerance of the dimension being inspected. Tolerances represent the allowable limits of variation in a physical dimension, which is crucial for ensuring that parts fit together correctly and function as intended.

In precision machining, when a dimension is critical, it often requires a highly accurate measuring instrument to ensure compliance with the specified tolerance. For example, if a tolerance is very tight (e.g., ±0.001 inches), a more sophisticated measuring tool such as a micrometer or a coordinate measuring machine (CMM) may be necessary to achieve the required accuracy. Conversely, for dimensions with looser tolerances, simpler tools like calipers may suffice.

The other factors, while relevant, do not primarily dictate the choice of measuring instrument as effectively as tolerance does. The material of the part might affect the method of measurement or the type of instrument used, but it does not drive the need for precision as much as tolerance. The cost of the instrument can represent a practical constraint but shouldn't overshadow the need for precision based on tolerance requirements. Lastly, the make and model of the machine may provide context on compatibility but is less critical than ensuring the instrument meets the tolerance specifications.