Press fit interference calculator
Find the minimum, maximum and mean interference of a shaft and hole pair from their tolerance limits.
How it is calculated
Minimum interference = shaft minimum − bore maximum. Maximum interference = shaft maximum − bore minimum. A positive value means the shaft is larger than the bore (interference).
Worked example
Shaft 25.030 to 25.050 mm, bore 24.990 to 25.000 mm: minimum = 25.030 − 25.000 = 30 µm, maximum = 25.050 − 24.990 = 60 µm.
Steps
- Enter the shaft limits from the drawing.
- Enter the bore limits from the drawing.
- Check the fit type: interference, transition or clearance.
Frequently asked questions
What interference is typical for a press fit?
It depends on size and materials. Many steel-on-steel fits use roughly 0.1 % to 0.2 % of the diameter, but follow the standard fit table (ISO 286) for your case.
Does this calculate the press force?
No. Press force depends on length, friction coefficient and stress. This tool gives only the radial interference.
Why are the results in µm?
Fit tolerances are small, so microns give readable numbers.
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References
ISO 286-1 and ISO 286-2 (ISO system of limits and fits). Use the fit tables for the preferred H7/p6 or similar designations.
Estimates for information only. Verify critical values with a qualified engineer or your supplier standards.