British standard limit system consists of 21 classes of fits and 16 grades of tolerances.
3) British standard limit system consists of
21 classes of fits and 16 grades of tolerances
Related Limits and Fits MCQ - Machinist(Set-1) with Answers
25.00 mm
A dimension is stated as Dia 25 H7 in a drawing. The lower limit is 25.00 mm.
For 25 H7 Tolerance Grade
Basic Size = 25.000 mm
ES = +21 Microns = 0.021 mm
EI = 0 Microns = 0.000 mm
Hence
Lower limit = Basic Size + EI = 25.000 + 0.000 = 25.000 mm
Upper Limit = Basic Size + ES = 25.000 + 0.021 = 25.021 mm
Hence A dimension is stated as Dia 25 H7 in a drawing. The lower limit is 25.000 mm.
0.04 mm
A dimension is stated as 25 +/-0.02 mm in a drawing. Then
Basic Size = 25.000 mm
Upper Tolerance = + 0.02 mm
Lower Tolerance = - 0.02 mm
Total Tolerance = 0.02 + 0.02 = 0.04 mm
Tolerance
Tolerance is defined as the difference between the maximum and the minimum sizes allowed in manufactured components.
Actual size
The measured size of the dimension of a component is called Actual size.