Preferred Force Shrink Fits Chart ANSI B4.1 Table Calculator

Engineering, Manufacturing Tolerance Limits Fits Charts

This Calculator will determine the preferred size and limit tolerances for a force or shrink fit per ANSI B 4.1.

FN 1 Light drive fits are those requiring light assembly pressures, and produce more or less permanent assemblies. They are suitable for thin sections or long fits, or in cast-iron external members.

FN 2 Medium drive fits are suitable for ordinary steel parts, or for shrink fits on light sections. They are about the tightest fits that can be used with high-grade cast-iron external members.

FN 3 Heavy drive fits are suitable for heavier steel parts or for shrink fits in medium sections.

FN 4 and FN 5 Force fits are suitable for parts that can be highly stressed, or for shrink fits where the heavy pressing forces required are impractical.

Other types of fits: See --> Preferred Tolerances & Fits Calculator RC - LT Fits

  • RC - Running or Sliding Fits
  • LC - Clearance Locational Fits
  • LT - Transition Locational Fits
  • LN - Interference Locational Fits


NOTE: Maximum Nominal Size Input to Calulator is Ø19.69".

Force or Shrink Fits Tolerances  per. ANSI B4.1 Table Calculator  
Enter the desired tolerance = 
Enter shaft nominal diameter (inch) =       
                  Max Min      
        Tolerance (thousandths in) =       
        SHAFT Diameter max / min in. =       
            Tolerance Zone =       
                  Max Min      
        Tolerance (thousandths in) =       
        HOLE Diameter max / min in. =       
            Tolerance Zone =       
                  Max Min      
        Interference (in) =       

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