Dimensions, tolerance and assemblies

Dimensions

Parallel Dimensioning/ Datum

Superimposed Running dimensioning

many dimension on the same surface of an object

reduce the amount of space used on a drawing. The origin point of the dimension is indicated by a small circle at intersection of the first dimension and projection line

Chain dimensioning

Each dimension is placed adjacent to the next dimension without there being a gap between each dimensioning

combined dimensioning

Uses both the chain and parallel dimensioning

Dimensioning small features

place arrow head outside of the extension line

dimensions not being able to see clearly

due to

Dimensioning of multiple features

use the same number of features( Circles) of the same dimension multiply by its dimension

dimensioning of radius

dimensioning radius with or without a center location

dimensioning of circle, arcs and holes

circle

Diameter

dimension by

arcs

Radius

dimension by

holes

located by

center line

dimensioning angles

marked with a curved dimension line and have a degree symbol

dimension should not be repeated

Tolerance

Bilateral Tolerance

the dimension can be both positive and negative

Unilateral Tolerance

dimension can only be in positive or negative

Limit Tolerance

the dimension is specific

upper limit - lower limit

Assemblies

clearance fit

interference fit

when the maximum allowed shaft size is smaller then the minimum allowed hole size

the external dimension of a part slightly exceeds the internal dimension of the part in which it is being fitted in

multiple parts are join together to make a larger product