Question

Which of the following is incorrect regarding terminology?

(a) Grades of tolerances decides manufacture’s accuracy

(b) For any basic size there are 20 different shafts

(c) Line of zero deviation is known as zero line

(d) Tolerance has no sign

I have been asked this question in exam.

The above asked question is from Terminology in section Limits, Fits and Gauges of Engineering Metrology

Answer 1

Correct option is (b) For any basic size there are 20 different shafts

The best I can explain: For any basic size, there are 25 different shafts. These are designated by small letters from a to zc. Each shaft has 20 tolerance grades. Tolerance is the algebraic difference between lower and upper deviation.