Understanding Tolerances in Small-Scale CNC Machining

Tolerance is the language of precision. Understanding what is achievable, and what it costs, helps you specify parts that fit without overpaying.

04 May 20263 min readGlobal3D Team

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Tolerance describes how much a dimension is allowed to vary, and it is central to any part that has to fit or mate with another. CNC machining holds tight tolerances well, but tighter is not always better, because precision has a cost.

Tolerance and cost

Holding a looser tolerance is quick and cheap, while a very tight one demands more careful machining, measurement and sometimes extra finishing. Calling out a tight tolerance on every dimension, when only a few really matter, drives up cost for no benefit.

The smart approach is to specify tight tolerances only where the part genuinely needs them.

Specify what matters

Tell us which dimensions are critical and which can be relaxed, and we will machine your CNC part to suit. That keeps the fit right and the price sensible.