What is required for each dimension on a technical drawing?

• A. A note of special instructions
• B. An exact measurement
• C. A tolerance
• D. A reference scale

Answer: (C)

For each dimension on a technical drawing, a tolerance is required because it defines the acceptable range of variation for that dimension. Tolerances are essential in manufacturing and engineering as they specify how much a feature can deviate from the exact dimension without compromising functionality or assembly. This allows for differences in manufacturing processes, material properties, and environmental conditions.

By including tolerances, designers communicate the level of precision needed for each dimension, which is crucial for ensuring parts fit and function as intended. This practice promotes efficient manufacturing and quality control, as each manufactured part can be checked against these tolerances to ensure compliance with the design specifications.

In contrast, while a note of special instructions, an exact measurement, or a reference scale can provide additional information on a drawing, they do not serve the fundamental purpose of conveying the acceptable limits of size and fit that a tolerance provides.