LIMITS, FITS AND TOLERANCES CALCULATOR (ISO SYSTEM)

Limits, fits and tolerances calculator was developed to calculate 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 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.

Limits and tolerances for shaft & hole fit

Calculator:

INPUT PARAMETERS
Parameter Value Unit
Nominal Size mm
Hole Tolerance ---
Shaft Tolerance ---
 


Note : Use dot "." as decimal separator.


RESULTS
HOLE
Parameter Value Unit
Designation --- ---
Hole Upper Deviation ---  μm(0.001mm)
Hole Lower Deviation --- μm(0.001mm)
Maximum Hole Size --- mm
Minimum Hole Size --- mm
SHAFT
Parameter Value Unit
Designation --- ---
Shaft Upper Deviation ---  μm(0.001mm)
Shaft Lower Deviation ---  μm(0.001mm)
Maximum Shaft Size --- mm
Minimum Shaft Size --- mm
FIT
Parameter Value Unit
Designation --- ---
Fit Type --- ---
Maximum Clearance --- μm(0.001mm)
Minimum Clearance --- μm(0.001mm)




Definitions:

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.

Supplements:

Link Usage
Preferred fits advised by ISO and ANSI metirc standards Preferred metric fits advised by ISO 286-1 (2010) and ANSI B4.2 (1978) standard are given to help user about the selection of fit. Whenever possible, selection of tolerance class shall be done among these tolerances to avoid too many numbers of tools and gauges.
Interference (press & shrink) fit calculator The calculator which calculates press fit force, required temperatures for shrink fit, fit stresses and other parameters necessary for interference fit design
Precision Measuring Tools For Shaft and Hole Measurements Devices that can be used for the measurement of the inside diameter of the hole and outside diameter of a shaft

Reference:
  • Oberg.E , Jones.D.J., Holbrook L.H, Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc., pp 648 - 671
  • IS0 286-1 (2010) Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 1: Basis of tolerances, deviations and fits
  • IS0 286-2 (2010) Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts
  • ANSI/ASME B4.2 (1978) Preferred Metric Limits and Fits