Nominal size usage: Is “nominal size” primarily used for general identification of features and commonly expressed as decimal values on modern drawings?

Introduction / Context:
Nominal size serves as the convenient identifier for features, part families, and catalogs (e.g., “20 mm shaft,” “8 mm hole”). While actual limits and tolerances govern manufacturing, the nominal value remains the nameplate reference used throughout design, purchasing, and communication.

Given Data / Assumptions:

• Nominal size is not a measured result; it labels the intended size family.
• Modern CAD/drawing practices frequently use decimal notation for clarity and consistency.
• Fractional notation still appears in some industries (e.g., construction fasteners), but decimals are prevalent in precision manufacturing documentation.

Concept / Approach:
Because decimals avoid ambiguity and align with metric practice and many inch-based machining standards, “usually expressed in decimals” is accurate as a general statement for modern technical drawings. The key point is that nominal size is for identification; limits/tolerances define acceptable variation around that nominal.

Step-by-Step Solution:
Recognize nominal = identifier, not measured outcome.Note that decimal notation is the common convention in engineering drawings for readability and precision.Acknowledge fractional use in specific domains but not as the dominant practice in precision drafting.Conclude the statement is generally correct.

Verification / Alternative check:
Review standard title blocks and dimensioning policies in manufacturing firms; decimal dimensioning is the norm, with specified decimal-place precision tying to tolerances.

Why Other Options Are Wrong:
Restricting correctness to metric, inch, or threaded features misunderstands that decimal-based nominal identification is widespread across domains.

Common Pitfalls:
Confusing nominal with actual; assuming fractional callouts imply fractional tolerancing without explicit limits.

Final Answer:
Correct