Limits, fits and tolerances calculator has been developed to calculate engineering tolerances of inner and outer features of journal bearings, linear bearings, thrust bearings, bushings, ball bearings, roller bearings, housings, cylinder bores, drilled holes, linear and precision shafts, pistons, etc. The calculator works in line with ISO 286-1 (2010), ISO 286-2 (2010) and ANSI B4.2 (1978) standards which are based on metric units. According to the input parameters of nominal size and hole/ shaft tolerances, size limits and deviations for hole/shaft are calculated and fit type is selected among the clearance, transition and interference fits. The schematic representation of the fit is also drawn. The preferred tolerances and fits advised by ISO and ANSI standards can be found in the "Supplements" section.
The tolerances defined in ISO 286-1 (2010) are applicable to size range from 0 mm to 3150 mm but there are a lot of exceptional
cases defined in the standard which depend on tolerance selection. If the
calculation results given by the calculator are "---", then this means the
input parameters are not applicable according to ISO standard.
Note: For more information on metric limits and fits including definitions, designations, symbols, preferred metric fits, fundamental deviations and calculation of limits of tolerance, please refer to pages 648 – 671 of the
Machinery's Handbook, 29th.
Nominal size: The size of a feature
of perfect form as defined by the technical drawing.
Deviation: The difference between a size and the corresponding nominal size.
Upper deviation: The difference between the maximum limiting size and the corresponding nominal size
of a feature.
Lower deviation: The
difference between the minimum limiting size and the corresponding nominal size
of a feature.
Tolerance: The difference
between the maximum and minimum size limits of a part.
Clearance Fit: A fit type where clearance exists between assembled parts under all tolerance conditions.
Interference Fit: A fit type where interference exists between assembled parts under all tolerance conditions.
Transition Fit: A fit type where clearance or interference can exist between assembled parts depending on tolerance conditions.
GD&T A means of dimensioning and tolerancing a part with respect to relationship and function of that part. GD&T is used to define how a part feature relates the other part features in the same part or in a mating part; it’s a way to dimension and tolerance with respect to part’s function, the way it works.