Millwright Level 1 Practice Exam

What type of tolerance allows for an exact size without variation?

1. Unilateral

2. Bilateral

3. Direct

4. General

The correct answer is: Direct

The correct answer is that a direct tolerance allows for an exact size without variation. In engineering and manufacturing, tolerances are critical as they define the allowable limits of variation for a given specification. Direct tolerance specifies a single dimension without any permissible deviation, meaning that a part must be manufactured with that exact measurement. This level of precision is essential in applications where the fit between components is crucial, and any deviation could lead to functional failure or diminished performance. The other types of tolerances mentioned, such as unilateral and bilateral, do allow some variation. Unilateral tolerances permit variation in one direction—either above or below the specified dimension—but not both. Bilateral tolerances allow variation in both directions, above and below the specified dimension, presenting a range of acceptable sizes that can deviate from the nominal value. General tolerances apply to various dimensions but also permit some level of variation, which is broader than the precise requirement of direct tolerance.