What are tolerances?
Tolerances refer to the amount a dimension my vary from it’s maximum to its minimum value. Tolerances can be indicated as a unilateral tolerance or a bilateral tolerance.
The Unilateral Tolerance (as shown) indicates the base dimension and how much the actual manufactured dimension may vary from this dimension.
As shown, the Internal Diameter (ID) may be, at a minimum 29,98 and the maximum of 30,02.
In the same way as the ID, the OD (Outer Diameter) has a minimum of 49,98 & a maximum of 50,02
The Bilateral Tolerance also indicates a maximum and minimum value. As the example shows, the minimum dimension the shaft may be is 30,06 and the maximum is 30,09