ANSI LIMITS, FITS AND TOLERANCES CALCULATOR

ANSI limits and fits calculator works in line with ANSI B4.1 standard which is based on inch units. According to nominal size and fit type selection among running and sliding [RC], locational clearance [LC], locational transition [LT], locational interference [LN], force and shrink [FN] fits, size limits for hole/shaft are calculated with schematic representation of the fit. ANSI tolerance calculator is applicable to non-threaded cylindrical parts.

Limits of sizes that calculated are the extreme values, within which the actual size of the dimension shall lie, at the standard temperature of 20C or 68F.

ANSI Limits, Fits and Tolerance Calculator:

INPUT PARAMETERS
Parameter	Value	Unit
Nominal Size		Inch
Fit Type	RC Running or sliding clearance fit LC Locational clearance fit LT Locational transition fit LN Locational interference fit FN Force or shrink fit
Fit Detail	RC1 Close sliding fits RC2 Sliding fits RC3 Precision running fits RC4 Close running fits RC5 Medium running fits RC6 Medium running fits RC7 Free running fits RC8 Loose running fits RC9 Loose running fits

Note : Use dot "." as decimal separator.

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RESULTS
HOLE
Parameter	Value	Unit
Hole Tolerance	---	---
Hole Upper Deviation	---	thou(0.001 inch)
Hole Lower Deviation	---	thou(0.001 inch)
Maximum Hole Size	---	inch
Minimum Hole Size	---	inch
SHAFT
Parameter	Value	Unit
Shaft Tolerance	---	---
Shaft Upper Deviation	---	thou(0.001 inch)
Shaft Lower Deviation	---	thou(0.001 inch)
Maximum Shaft Size	---	inch
Minimum Shaft Size	---	inch
FIT
Parameter	Value	Unit
Fit Type	---	---
Maximum Clearance	---	thou(0.001 inch)
Minimum Clearance	---	thou(0.001 inch)

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.

Hole Basis Fit System: A fit system in which hole lower deviation is zero. In other words the lower limit of size of hole is equal to nominal size. The required fit (clearance, interference etc.) is obtained by keeping hole as defined and applying various tolerance classes to shaft.

Allowance:  The difference between the maximum material limits of mating parts. Minimum clearance (+ allowance) or maximum interference (- allowance) between parts depending on the fit type.

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:

• Limits, fits and tolerances (ISO and ANSI Systems)
• Interference (press & shrink) fit calculator
• Preferred tolerances and fits charts (ANSI)
• Precision Measuring Tools For Shaft and Hole Measurements

Reference:

• ANSI/ASME B4.1 - 1967 (R2004) Preferred Limits and Fits for Cylindrical Parts
• Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
• Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc.