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Category: GD&T Symbol Rules and Examples

Articles related to GD&T symbol rules and walk-through examples of GD&T Symbols and their uses

Circularity – The Tolerance Zone

by Brandon John on June 22, 2021.

There can be a lot of confusion when dealing with circularity – especially when identifying the tolerance zone compared to how Rule #1 controls it.  In this video, we provide a visual example to review how rule #1 controls circularity within the area between two concentric circles.

Position vs. Symmetry – Relative to a Datum Axis

by GD&T Basics on May 24, 2021.

This video is in response to a question that we received on our question line from Alex.  His question is as follows: “Is there a best-practice way to use Position (instead of Symmetry) to control two planar surfaces situated on the sides of a round shaft, by using the round section’s axis as a datum?  Since Position for planar features...

Virtual Condition – Does it apply at RFS?

by GD&T Basics on May 5, 2021.

In this question line video, Brandon discusses Virtual Condition and whether it can apply at Regardless of Feature Size (RFS). What is Virtual Condition (VC)? When a feature is controlled with the Maximum Material Condition (MMC) modifier or Least Material Condition Modifier (LMC), a size boundary is created based on the collection of geometric and size tolerances. This boundary is...

Profile of a Surface – Unilateral vs. Bilateral

by GD&T Basics on April 12, 2021.

What is the difference between unilateral and bilateral tolerance in a profile of a surface callout? In this post, Brandon explains the difference and gives examples of how they are used.     Profile of a Surface When applying a 3-Dimensional tolerance zone around a surface, usually a curved shape but could be any, the Profile of a Surface symbol...

Profile of a Line Tolerance Zone

by GD&T Basics on April 6, 2021.

This video is in response to a question that we received on our question line from Amar. Amar’s question is as follows: “If we are given a BASIC radius of 10mm, and on the radius, we are applying a Profile of a Line Tolerance of 0.6mm, what will be the max & min size of the radius & what will...