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Mmc Calculator

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In the realm of manufacturing and engineering, precision is paramount. The Maximum Material Condition (MMC) calculator emerges as an indispensable tool, designed to calculate the MMC for parts, ensuring they fit together with optimal precision. This innovative tool caters to both internal features, like holes, and external features, like shafts, aiding in achieving the highest quality in product assembly.

Purpose and Functionality

The MMC calculator is grounded in the principles of geometric dimensioning and tolerancing (GD&T), specifically addressing the concept of MMC. It provides a straightforward method to determine the maximum size of a part within specified tolerance limits, thus ensuring that parts will fit together as intended, even under the most restrictive conditions.


To find the Maximum Material Condition (MMC) for a part, you can use a simple rule:

  • For a hole (or any internal feature): Subtract the tolerance from the nominal size. This gives you the smallest the hole can be, meaning there’s the most material around it.MMC for a hole = Nominal Size – Tolerance
  • For a shaft (or any external feature): Add the tolerance to the nominal size. This gives you the largest the shaft can be, meaning there’s the most material in the shaft itself.MMC for a shaft = Nominal Size + Tolerance

The Formula Explained

The calculator utilizes two primary formulas, contingent on the feature type:

  • Internal Feature (Hole): MMC = Nominal Size - Tolerance
  • External Feature (Shaft): MMC = Nominal Size + Tolerance

These formulas yield the MMC by accounting for the nominal size of the feature and its tolerance range, ensuring the feature contains the maximum material allowable for proper assembly.

Step-by-Step Examples

Example for an Internal Feature (Hole)

  • Nominal Diameter: 10mm
  • Tolerance: -0.2mm

Calculation: MMC=10mm−0.2mm=9.8mm

Result: The hole’s MMC is 9.8mm, indicating the smallest permissible diameter.

Example for an External Feature (Shaft)

  • Nominal Diameter: 10mm
  • Tolerance: +0.2mm

Calculation: MMC=10mm+0.2mm=10.2mm

Result: The shaft’s MMC is 10.2mm, denoting the largest permissible diameter.

Relevant Information Table

Feature TypeNominal SizeToleranceMMC CalculationMMC Result
Hole10mm-0.2mm10mm – 0.2mm9.8mm
Shaft10mm+0.2mm10mm + 0.2mm10.2mm


The MMC calculator transcends being a mere tool; it embodies a critical component in the design and manufacturing process, particularly in fields demanding high precision, like aerospace and automotive engineering. By ensuring parts meet MMC criteria, manufacturers can guarantee optimal fit and functionality, thereby enhancing product reliability and performance. In essence, the MMC calculator not only simplifies complex calculations but also serves as a beacon of precision in the engineering world, fostering innovation and excellence in product design and manufacturing.

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