How Tight Should CNC Tolerances Be?

Tolerances tell the machinist how precise each dimension has to be — and they have a big effect on cost. The goal isn't the tightest possible tolerance; it's the right tolerance for each feature. Tight where the part's function truly needs it, looser everywhere else. Getting that balance right controls cost without compromising the part.

Why Tolerances Drive Cost

Holding a tight tolerance takes more time, care, and sometimes special processes — all of which cost money. A part where every dimension is tightly toleranced is far more expensive than one where only the critical features are, even if most of the part is identical.

Tight Only Where It Matters

The features that mate with other parts, seal, or bear load usually need real precision. Many other dimensions don't — and toleranced loosely, they save money with no downside. The skill is deciding which is which.

Match Tolerance to Function

Common Mistakes We See

A Good Next Step

A short conversation can help you think through which tolerances your part really needs tight — and where loosening them saves money.

Please keep your question general — no confidential product details are needed for the introductory consultation. If confidential review is needed later, an NDA can be arranged before a longer engagement.