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Precise Profile Tolerances

At Mid-States Aluminum, we understand the mechanics of working with aluminum. For each part we manufacture, we consider wall thickness, profile circumscribing circle size, location of dimension on the profile and the type of profile. We are also able to match the tolerance specifications with the right extrusion press size.

While the aluminum industry provides standard dimensional tolerance guidelines for extruded aluminum profiles — flatness and twist, contours, straightness — the experience our team brings to each project allows us to compensate for those unique situations where standard tolerances will not be successful in the end-use part application.

We understand that each extruded profile has critical features that are important to its performance. Our expertise helps us determine when tolerances must be tightened to achieve the fit, form and functional requirements of the end applications.

General Guidelines for Standard Tolerances

  • For linear cross section dimensions, use ± 0.008" per inch of the dimension.
  • For wall thickness, use ± 10% of the specified dimension.
  • For twist, use ½ degree per foot of length
  • For straightness, use 0.0125" per foot of length.
  • Angularity will vary with wall thickness and size of the surface but are generally between ±1 degree and ±2 degrees.


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