Guides / Process
5-Axis Machining Tolerances: What Is Realistic on Your Drawing
September 20, 2026
A tolerance on a drawing is a promise: the finished feature will fall inside a stated range around the nominal dimension. On a 5-axis part, the tolerance you write down affects three things at once, the machine time needed to hit it, the inspection needed to prove it and the number of shops willing to quote it at all.
What tolerance actually costs
A general tolerance of ±0.1 mm needs one finishing pass and a caliper check. A tolerance of ±0.01 mm on the same feature needs a slower finishing pass, a more rigid setup and often a CMM report to prove the part is in spec. The dimension did not get ten times harder to cut. The proof that it is correct got several times more expensive.
This is why two drawings that look almost identical can quote very differently. The feature list is the same. The tolerance column is not.
What a 5-axis shop can hold as standard
Most 5-axis shops treat the following as standard work, achievable without special fixturing or a controlled environment:
| Material | Typical tolerance |
|---|---|
| Aluminum 6061 / 7075 | ±0.01 to ±0.025 mm |
| Stainless steel 304 / 316 / 17-4 | ±0.01 to ±0.025 mm |
| Titanium Grade 2 / Grade 5 | ±0.01 to ±0.025 mm |
| Nickel alloys (Inconel) | ±0.025 mm is a safer target |
| Plastics (PEEK, POM, PTFE) | ±0.05 mm is realistic |
Tighter numbers exist. Shops running temperature controlled rooms and jig grinding can hold a few microns on a critical bore. That level of control is a specialty, not a default, and it prices like one.
Position tolerance is where 5-axis earns its keep
The tolerance that matters most on a multi-face part is often not a single dimension but the position of features relative to each other, a bore on one face lining up with a bore on another. On a 3-axis mill that relationship needs two or more setups, and every setup adds a small stack of error from re-fixturing.
A 5-axis machine holds the part in one clamping and reaches every face without moving it. The position tolerance between features on different sides of the part is limited mostly by the machine’s own accuracy, not by how many times the part was unclamped. This is the real reason 5-axis parts hold tighter relationships between faces. It is not that the linear axes are inherently more precise than a good 3-axis machine.
How shops price a tight tolerance
Three things usually rise together when a tolerance tightens: cycle time, tooling wear and inspection. Cycle time rises because finishing passes get lighter and slower to reduce deflection and heat. Tooling wear rises because holding size consistently needs sharper, more frequently replaced edges. Inspection rises because a caliper is no longer enough proof, so the shop needs a CMM cycle and sometimes a fixture built just to hold the part during measurement.
None of this shows up as a separate line on most quotes. It is folded into the part price, which is why the same geometry can price very differently once the tolerance column changes.
Where tight tolerance is worth paying for
Tolerance the features that have a functional reason to be tight:
- Bores or bosses that mate with another part
- Sealing faces and O-ring grooves
- Bearing seats and shaft fits
- Positions that must line up across faces for assembly
Everywhere else, a general tolerance of ±0.1 mm, or your shop’s own standard, is enough. A drawing with one tight functional bore and a sensible general tolerance is both cheaper and easier to quote accurately than one where every dimension carries the same tight number out of habit.
Reading tolerance callouts across competing quotes
When you compare quotes, check that every shop is pricing the same tolerance, not just the same nominal dimensions. A shop that assumes your unmarked dimensions carry a loose commercial tolerance will always look cheaper than one that assumes ±0.05 mm by default. Put a general tolerance note on the drawing, for example “unless noted, ±0.1 mm,” so every shop prices the same scope.
Also ask what “in tolerance” means for the report you get back. First article inspection with a full CMM report against every callout is a different scope, and a different price, than a shop’s word that the part passed a spot check.
How to write the drawing so you do not overpay
Use GD&T for the relationships that actually matter, position and perpendicularity on mating features, rather than a tight bilateral tolerance on every dimension. A profile tolerance on a curved surface communicates intent more clearly than a string of individual coordinate tolerances. And say what the tolerance is for. A shop that knows a bore locates a bearing will pick the right fixturing and inspection method on the first try instead of guessing.
If you inherited a drawing with tolerances tighter than the part needs, ask your shop which ones actually drive the price before you loosen anything. Sometimes the expensive dimension is not the one that looks tightest on paper.
What to send with your RFQ
A STEP file plus a PDF with the tolerance and GD&T callouts gets the most accurate quote. If you are not sure which tolerances matter, say so and describe what the part mates with. A shop that understands the assembly can often suggest which numbers to tighten and which to relax.
The short version
Tolerance costs money through inspection and slower finishing, not through the size of the number alone. Reserve tight tolerances for mating and sealing features, let a general tolerance cover the rest, and rely on a 5-axis machine’s single setup to hold position between faces without paying for tighter linear tolerances than the part needs.
This post is part of our guide to 5 axis machining quality control.
See also: 5-Axis Machining Tolerances by Feature and What They Cost.
Frequently asked questions
What is a typical tolerance for 5-axis machined parts?
±0.01 to ±0.025 mm is common for aluminum and stainless parts on a well maintained 5-axis machine. Tighter numbers are possible but should be reserved for the features that actually need them.
Does 5-axis machining hold tighter tolerances than 3-axis?
Not because the axes themselves are more accurate. It holds tighter position between features because the part is machined in one setup, so nothing shifts between operations.
Why did tightening one dimension raise my whole quote?
A single tight tolerance can force slower finishing passes and extra inspection on the whole part, not just that feature. Ask the shop to quote the tight feature and the general tolerance separately so you can see the split.
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