Chapter 10 Dimensioning
265
in the chart, and the chart shows the metric
and inch equivalents of each dimension.
Metric Dimensioning with a
Conversion Chart
When a part is designed to metric standards,
the engineering drawing is made with metric
dimensions. A note on the drawing informs the
person reading the drawing that all dimensions
are in metric units. Some metric drawings
provide a conversion chart, Figure 10-35. The
chart shows metric dimensions in the left
column and the inch equivalents in the right
column. This method permits a comparison of
values.
Metric Dimensioning (Metric
Units Only)
Some metric drawings provide metric
dimensions only, Figure 10-36. This method is
Dual dimensioning is the most complicated
dimensioning system. It is seldom used today.
However, large numbers of dual-dimensioned
drawings are still in use. This method is
presented in this text so that you will be aware
of its existence.
Dimensioning with a Tabular Chart
When a drawing is shown with both inch and
metric dimensions, a tabular chart is sometimes
used. See Figure  10-34. With this technique,
the dimensions are labeled with letters (A, B,
C, etc.) rather than sizes. The letters are listed
Note indicating
how metric
dimensions
are identified
Thread note
(inches only)
Goodheart-Willcox Publisher
Figure 10-32. A dual-dimensioned drawing. Inch dimensions are given first. The thread size is not given in metric
units because there is no metric thread this size.
.753
19.13
Position Method
.753
[19.13]
Bracket Method
Goodheart-Willcox Publisher
Figure 10-33. Methods of indicating inches and
millimeters on a dual-dimensioned drawing.
Copyright Goodheart-Willcox Co., Inc.