IT Grade refers to the International Tolerance Grade of an industrial process defined in ISO 286. This grade identifies what tolerances a given process can produce for a given dimension.
The specific Tolerance for a particular IT grade is calculated via the following formula:
where:
- T is the tolerance in micrometres
- D is the geometric mean dimension in millimeters
- ITG is the IT Grade, a positive integer.
One thinks of as being the key dimension on the part and as being the required tolerance on that key dimension. The larger the ITG, the looser the tolerance.
Read more about IT Grade: Meaning and Interpretation, Alternate Formulation
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