Guides / Process
Metal Stamping Tolerances: What's Realistic and What Costs Extra
October 3, 2026
A print with every dimension held to the same tight tolerance is one of the fastest ways to get an inflated stamping quote. Most parts do not need every dimension held equally tight, and a stamping shop that gets a print with no distinction between critical and non critical dimensions has to price every one of them as if it mattered.
Standard tolerance ranges by feature type
These are typical achievable ranges for common thicknesses in cold rolled steel on a progressive or transfer die. They move with material, thickness, part size and die condition, so treat them as a planning reference, not a spec to copy onto a print.
| Feature | Typical tolerance |
|---|---|
| Hole position | ±0.05 to 0.1 mm |
| Hole diameter | ±0.05 to 0.1 mm |
| Outline (blanked edge) | ±0.1 to 0.15 mm |
| Formed dimension (bend, form height) | ±0.15 to 0.3 mm |
| Flatness, unformed area | 0.1 to 0.2 mm per 100 mm, typical |
| Bend angle | ±0.5 to 1 degree |
Thinner material and simpler features track toward the tight end of these ranges. Thicker material, larger parts and deep forms track toward the wide end, and can fall outside it depending on the geometry.
Why formed features carry wider tolerances than blanked ones
A punch cutting a hole or an outline removes material to a fixed die dimension, and that dimension does not change much as long as the tooling is sharp. Forming is different: the material is bent or drawn, and it relaxes slightly once the punch releases, a behavior called springback. Springback is not constant. It shifts with material lot, temperature, lubrication and how worn the die is. A shop building in a wide tolerance on formed dimensions is not being imprecise, it is pricing a real physical behavior that even a well maintained die cannot fully eliminate.
What drives the cost of holding a tighter tolerance
- Added stations. A tolerance tighter than standard sometimes needs a dedicated coining or restrike station to correct springback, which adds a station to the die.
- Harder tool steel and coatings. Tighter tolerances need components that hold their dimension longer as the die wears, which pushes toward more expensive steel grades and surface coatings.
- More frequent maintenance. A die holding a tight tolerance drifts out of spec sooner as punches wear, so it needs sharpening and adjustment more often, which is a recurring cost, not a one time one.
- Slower press speed. Some tight tolerance features run more reliably at a slower stroke rate, which lowers throughput and raises piece price.
- More inspection. Tighter tolerance usually means more frequent in process checks to catch drift before parts go out of spec, which adds labor to the piece price.
None of this means tight tolerances should be avoided. It means they should be spent on the dimensions that actually need them.
Mark the print so only the real criticals get priced tight
- Flag critical dimensions explicitly, with a note or a symbol, rather than leaving every dimension at the same tolerance block in the title block.
- State standard shop tolerance for everything else, so the shop knows what is not being asked to hold tighter than typical.
- Separate position tolerance from size tolerance on holes, since they can have different real requirements, for example a mounting hole where position matters more than exact diameter.
- Call out flatness only where it functionally matters, such as a sealing surface, rather than as a blanket spec across the whole part.
- Reference forming tolerance to the feature, not the whole part, since a bend height tolerance does not need to apply to the flat sections around it.
A print that distinguishes true criticals from the rest lets a shop price tight tolerance where you actually need it and standard tolerance everywhere else, instead of quoting the whole part at your tightest callout.
Questions to ask when a quote assumes a tolerance you did not specify
- Which tolerance standard are you quoting to if my print does not state one?
- Which dimensions on my print, if any, would you flag as difficult to hold at standard tooling?
- Does holding my callouts need an added station, and what does that add to tooling price?
- How does tolerance on this part change over die life, and when would you expect to need a rebuild to hold it?
Where we fit
Send your print through our RFQ form and we match it with up to three stamping shops that can speak to your specific tolerances, not a generic range, then reply within 24 business hours. For the rest of what a shop needs to quote accurately the first time, see the RFQ checklist.
Frequently asked questions
What tolerance can a standard progressive die hold?
As a general range, plus or minus 0.05 to 0.1 mm on hole position and size, and plus or minus 0.1 to 0.15 mm on outline dimensions, for common thicknesses in cold rolled steel. This is typical, not a guarantee. Material, thickness, part size and die wear over life all move the real number, so confirm achievable tolerance with the shop quoting your specific part.
Why does my formed dimension have a wider tolerance than my flat dimension?
Forming introduces springback, where the material relaxes slightly after the punch releases it. Springback varies with material lot, temperature and die wear, which makes formed dimensions inherently less repeatable than dimensions cut directly by a punch. Shops account for this with a wider tolerance band on formed features.
Does tighter tolerance always mean a more expensive die?
For the features held to that tolerance, usually yes, since it can mean added stations, secondary coining, harder tool steel, or more frequent maintenance to keep the die within spec as it wears. It does not mean the whole part gets more expensive if only a few features are called out tight and the rest use standard shop tolerance.
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