2. Tolerance

There are two types of tolerances:

• bilateral tolerances, comprising an upper tolerance Ts and a lower tolerance Ti (e.g. 10° ± 1°);

• the upper or lower unilateral tolerance (e.g. 10° maximum).

They are linked to specifications that must be defined after tolerancing in the design phase.

• Tolerance interval

  Tolerance limits are used to define the IT tolerance interval, only in the case of bilateral tolerances:

  IT = upper tolerance – lower tolerance

• Nominal value centered

  The centered nominal value is also known as the...