Have a sheet metal project in mind? Not sure what tolerances to use? Don’t worry.
Here are some basic tolerances you can use to build your own sheet metal components and parts, from our 75+ years of experience.
In the absence of drawing tolerances, your part(s) will be manufactured as per Tripar’s default tolerances below.
The sketch above is for illustrative purposes only.
Standard Default Tolerances
| DIM | Tolerance (“ ±) | Description |
|---|---|---|
| ±0.010” | Holes1 & linear dimensions of flat pieces < 0.5” | |
| ±0.015 | Holes1 & linear dimensions of flat pieces 0.5”< 4.0” | |
| ±0.020 | Holes1 & linear dimensions of flat pieces 4.0” < 12.0” | |
| Upon Review | Holes1 & linear dimensions of flat pieces > 12.0” | |
| A | ±0.010 | End to hole or bend |
| B | ±0.010 | Hole center-to-center (on one surface/plane) |
| C | ±0.015 | Bent edge to hole2 |
| D | ±0.020 | Distance over 2 bends2 |
| E | Undefined (TBD) | Distance over 3 or more bends2 |
| F | ± 2° | Angles3 |
| R | 1-2X Material thickness | Inside bend radii |
1 If the hole is not round, the above ranges apply to the largest dimension in the opening.
2 As measured nearest to bend(s).
3 Thin metals have some flexibility, and thus can deflect, even under their own weight. As such, tolerance applies up to 1” from the bend. For reference; 2° over 1” = .034”.
For those who provide, or are considering providing their own tolerance drawings, please see the following two TriparTech article on this subject, as well a sound sheet metal design practices.
Finish
Surface Finish: Shall be in accordance with material specified and associated governing specifications.
Formed or bent parts may have small surface blemishes near the areas of transition.
Residue: Metal fabricated parts are often produced and may be shipped with lubricants or dry film lubricants.
Protective Film: For raw materials which come with a protective film, parts shall be provided with this film, to help protect the parts until you, the customer remove when desired.
Burrs
Please note: having minimal small burrs is a normal part of metal stamping and CNC fabrication processes. Being nearly impossible to quantify & measure, unless otherwise specified, parts are provided in their “as stamped” or “as fabricated” condition. Additional costs for deburring (as an extra operation) can be arranged if need be.
