Which is the correct definition of regardless of feature size? O a) Regardless of where a feature of size lies within its form tolerance, the tolerance of size must be met. O b) Control placed on a feature of size stating that the tolerance of form or position must be met regardless of where the feature lies within its form tolerance O c) Regardless of where a feature of size lies within its size tolerance, the tolerance of size must be met O d) Control placed on a feature of size stating that the
The Correct Answer and Explanation is :
The correct definition of “regardless of feature size” is:
b) Control placed on a feature of size stating that the tolerance of form or position must be met regardless of where the feature lies within its form tolerance.
Explanation:
In Geometric Dimensioning and Tolerancing (GD&T), the term “regardless of feature size” refers to a specific type of tolerance applied to features of size, such as holes, shafts, or other dimensions that define the size of a part. This concept is essential in cases where a feature has both a size tolerance and a form or positional tolerance.
The main idea is that the tolerance for form (such as straightness, flatness, or circularity) or positional tolerance (such as location or orientation) must be maintained regardless of where the feature lies within its size tolerance range.
Let’s break it down:
- Feature of Size: A feature of size refers to a physical dimension of the part that has both a maximum and minimum size limit. This is often a hole, shaft, or any other feature that has a defined size tolerance.
- Form Tolerance: Form tolerances define the allowable variation of the shape of the feature. This can include straightness, flatness, circularity, or cylindricity.
- Positional Tolerance: This defines the allowable deviation of a feature’s location relative to a reference point or plane.
- “Regardless of feature size”: When a tolerance is placed with the phrase “regardless of feature size,” it means that the feature’s form or position must meet its specified tolerance limits no matter if the feature is at the maximum or minimum size within its allowable size range.
For example, if a hole has a size tolerance of 10 mm ± 0.1 mm, and a positional tolerance of 0.2 mm, “regardless of feature size” means that the hole’s position tolerance must be within 0.2 mm regardless of whether the hole is at the upper limit (10.1 mm) or the lower limit (9.9 mm).
This ensures that even if the part is produced at the extreme ends of the allowable size range, the form and positional tolerances will still apply, ensuring functional performance and quality consistency across different variations of the part.
Thus, option b correctly captures this concept.