Note: A dimension which is not to scale is shown underlined
Examples of chain and parallel dimensioning are shwon above. The advantage of parallel dimensioning is that there is no build-up of tolerances.
Dimensioning a brokent feature.
Dimensions of diameters are shown on view providing greatest clarity
Metric Screw Threads
Classes of Fit
If one class is shown for a male thread i.e 6g then the tolerance applies to the pitch dia and the major diameter. A dual tolerance is shown (5h6g) when a different tolerance is applied to the Pitch dia (5h) and the major dia (6h). The same principle applies to the female thread e.g. a tolerance grade (6H ) applies to both pitch dia and the minor dia. A tolerance grade (6H7H) refers to 6H for the pitch dia and 7H for the minor dia.
The typical designation for a thread on a drawing is as follows
The typical designation for a Pipe Threads
Useful Links On Drawing/ Dimensioning