Definition of Tolerance:
The components are manufactured that all lie in between
maximum and minimum limits.
The basic dimensions are called the normal or basic size
while the difference between the two limits is called permissible tolerance.
Tolerance is defined as the permissible variation in the dimension of the components.
Tolerance has two systems of specifications :
- Unilateral
- Bilateral
In machine design, there are two basic systems for giving
tolerance to the shaft or hole :
- Hole basis system
- Shaft basis system
According to the Bureau of Indian Standards, tolerance is
specified by an alphabet, capital or small followed by number Example: G8 or h6
There are eighteen grades of tolerances: IT1, IT2 up to IT18
The letters of symbol IT stand for INTERNATIONAL TOLERANCE
GRADE