CNC Machining Tolerance


CNC machining tolerance refers to the range of dimensional changes caused by machining errors or material changes when numerically controlled machining is performed on a CNC machine tool. The tolerance size of CNC machining will affect the accuracy and function of parts, so reasonable control and adjustment are required. The tolerance of parts is usually measured from the following 4 aspects.


The tolerance range of CNC machining is affected by many factors and has always existed. It is also a recognized normal phenomenon in the machining industry. Therefore, even the most powerful CNC machining company cannot produce parts with zero tolerance. But this does not mean that we can not pay attention to tolerances. On the contrary, in order to improve the quality of batch manufacturing, we should pay more attention to the factors that affect CNC machining tolerances.

CNC Machine

As we all know, CNC lathe tolerances and CNC milling machine tolerances are obviously different.

Machining Tool

The selection of a tool with high precision and less wear can reduce the machining tolerance.

Material Properties

Different materials have different machining properties, and some materials are not easy to cut.

Structure & Design

The internal structure and overall design of the part are also important factors that affect tolerances.

Tolerance type

There are four main types of tolerances used for CNC parts.

Standard CNC Tolerances

Bilateral Tolerance

Unilateral Tolerance


Our standard CNC tolerance is +/- 0.005 inches (0.13 mm). But if you need more accuracy, our standard accuracy or production machining tolerance is +/-0.002 inches (0.051 mm). We are also able to maintain +/- 0.0005 in. (0.0127 mm) on reamed holes and +/- 0.002 in. (0.051 mm) on feature locations.

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