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Tag: flatness

Flatness or Parallelism

by Crystal Bemis on September 8, 2025.

In this Question Line video, Jason reviews a submitted drawing, explaining the difference between flatness and parallelism, and gives options on how to tolerance the drawing based on what is critical to the design.

Flatness and Rule #1

by Crystal Bemis on February 10, 2025.

In this Question Line video, Jason explains how to calculate the flatness tolerance of a surface for a given example based on the size tolerances and Rule #1.

When to Use DMP Flatness

by Crystal Bemis on July 18, 2024.

Brandon explains DMP flatness, its potential issues when used on stacking parts, and an alternative method for controlling flatness on these parts.

Surface Finish and Flatness

by Crystal Bemis on May 15, 2023.

Surface finish and flatness both limit the amount of variation in a surface – one at the micro level and one at the macro level. Is it permissible to call out both on the same surface?

Can GD&T Flatness be used on a Datum?

by Tom Geiss on May 18, 2020.

Check out this question brought up about Flatness in our GD&T Fundamentals Course. We get a lot of questions about when flatness can be applied and how datums can be used with this. There are...

Flatness

by Tom Geiss on November 3, 2014.

Controls how flat a surface must be. No datums needed — it's self-contained, making it one of the simplest form tolerances to apply.