Not only do you need to describe the shape of an object, but also you must
give the design a complete size description; you must give it dimensions,
Always give dimensions that are convenient for the shop worker or
production manager. Work should never stop for mathematical computations
that should have been on the drawing. Make dimensions clear and concise
without duplication or the necessity to calculate, scale, or assume.
Two general types of dimensions are size dimensions and location
dimensions. Size dimensions define the size of the simple geometric shapes
within a part. An example of a size dimension is the diameter of a hole or
the width of a slot. Location dimensions define the location of these
geometric shapes in relation to each other. An example of location
dimensions is how far apart holes or slots are from each other.
Dimension your drawings by first geometrically analyzing the object and then
reviewing the procedures by which the object will be made and surfaced.
To analyze a dimension problem, follow this table:
Mentally divide the object into component geometric shapes.
Place size dimensions on each component part where they best
describe the object.
Select a locating centerline.
Place location dimensions so that each geometric shape relates to a
centerline or finished surface.
Add overall dimensions (length, width, and height).
Add all notes required to complete the description of the object.
Continued on next page