Topic: Metrology and Inspection
A basic hole is one whose
- A. Lower deviation is zero
- B. Upper deviation is zero
- C. Lower and upper deviations are zero
- D. None of the above
Answer: A. Lower deviation is zero
Explanation: In a hole-basis system for tolerances and fits, a basic hole is formally defined as a hole whose lower deviation is exactly zero. (Similarly, a basic shaft is one whose upper deviation is zero.)