Limits and fits — deviation terminology The algebraic difference between the maximum limit of size and the basic size is termed the __________.

Introduction / Context:
Limits, fits, and tolerances form the language of interchangeable manufacturing. Correctly naming deviations avoids confusion when reading drawings and specifying gauges.

Given Data / Assumptions:

• Basic size is the nominal reference dimension.
• Maximum and minimum limits define the permissible size range.
• Deviations are algebraic differences from the basic size (with sign).

Concept / Approach:
Upper deviation = maximum limit − basic size. Lower deviation = minimum limit − basic size. Tolerance = maximum limit − minimum limit (always non-negative). Fundamental deviation is the one deviation (upper or lower) farther from zero that defines the position of the tolerance zone with respect to the basic size system (e.g., hole basis H has zero lower deviation). Actual deviation refers to a particular measured size minus basic size, not the limit itself.

Step-by-Step Solution:
Write definition: upper deviation = max limit − basic size.Compare with alternatives to ensure consistent terminology.Select 'upper deviation' as the correct term.

Verification / Alternative check:
Standards such as ISO system of limits and fits (e.g., ISO 286) define upper and lower deviations precisely as above; engineering metrology texts use the same convention for both hole and shaft systems.

Why Other Options Are Wrong:
Lower deviation uses the minimum limit; actual deviation is based on a specific measurement; fundamental deviation identifies the tolerance zone position; tolerance is the width of the zone, not a deviation from basic size.

Common Pitfalls:
Ignoring algebraic signs leading to wrong clearance/interference values; mixing up hole-basis and shaft-basis conventions; assuming tolerance equals deviation.

Final Answer:
upper deviation