Primer on Metal and Steel Dimension Tolerances, Part 2

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Primer on Metal and Steel Dimension Tolerances, Part 2

metal steel dimension tolerances

In part one of this two-part blog series, we went over some of the basics on metal and steel tolerances and the impact they have on sheet metal and other metal orders. Tolerances, which refer to acceptable variations in size and dimensions compared to the original order, hold benefits for both the metal manufacturer and those purchasing their products.

At Wasatch Steel, we’re happy to explain tolerances and acceptable tolerance ranges for any of our steel sheet, steel pipe or other steel products, for which we also offer a variety of additional steel services. Tolerances come in several forms and sizes, plus may differ depending on the rolling format used for the sheet in question – today’s part two will dig into these important areas as you consider tolerance ranges for your next steel order.

Tolerance Types

In many cases, tolerances will be used to describe lengths and widths. However, they may also be used for boundary definitions on thickness requirements within a given piece of metal – not only does a full metal sheet have tolerances, individual holes, slots, grooves and various perforations all can have their own individual tolerances as well. Our pros will be happy to explain any of the tolerance formats you may run into while ordering from us.

Tolerance Range Sizes

In addition, it’s important to note that the application in question generally defines how large or small a given tolerance range is. The full range of tolerances you might find for a given metal sheet looks something like this:

  • Large range: 2 inches, plus or minus 0.250 inch
  • Medium range: 2 inches, plus or minus 0.125 inch
  • Small range: 2 inches, plus or minus 0.0625 inch
  • Very small range: 2 inches, plus or minus 0.006 inch

In certain cases, tolerance may be asymmetrical to help achieve the desired nominal dimension. The maximum and minimum ranges here tend to be roughly 0.005 inches.

Rolling Format

On top of the above, it’s important to note that the type of rolling format used in creating a steel sheet plays a role in tolerance as well. Hot-rolled steel, for instance, is generally the chosen format when dimensional tolerances are not a high priority compared to material strength – and also when smooth surfaces are not too big a deal.

Cold-rolled steel, however, is hot-rolled steel that’s been additionally processed, bringing more precise dimensions and surface properties. For this reason, cold-rolled steel is usually chosen if tolerances are a high priority, as cold-rolled sheets have much thinner tolerance ranges. This is why you generally see cold-rolled steel in applications like medical devices, auto engine parts and aerospace components, which require significant detail and precision.

For more on metal and steel tolerance ranges, or to learn about any of our steel products, speak to the staff at Wasatch Steel today.