Types and Applications of
tolerances in manufacturing drawings
Dear
Reader,
Days
have gone when mating parts were manufactured with physical reference of each
other. In modern designs parts are manufactured
with
specific tolerance to each dimension and hence interchangeability is obtained.
There are only two types of
tolerances.
1. Dimensional tolerances.
2. Geometrical tolerances.
1.Dimensional
tolerances.
Name
it self states that this type of tolerance is related to dimensions of a
feature.
Example:
Length in mm shown as 20.00±0.02 and Diameter shown as
10-0.02/-0.04
Means manufacturer has been given freedom of 20µ on each side
for
length ,he may produce a part with length 20.02 Or 19.98 mm.
And
diameter should be not more than 9.98 mm and less than 9.96 mm.
2. Geometrical tolerances.
Less
related to dimensions and more related to characteristics of one or
more
features.
Example:
Step with Diameter 8.00mm should be concentric within circular spread of 0.04
mm with step diameter represented by
datum A i.e. Dia 10.00 mm.ie concentricity at each section over the length in
between two cylindrical geometries.
nice
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