The #X designator is used to prevent redundant dimensions when a print has multiple identical features or a pattern. The number placed in front of the X represents the number of repetitive features that the dimension applies to. This designator is commonly used for holes, radii, chamfers, surfaces, and any other types of repetitive features.
The figure below shows an example of when the #X designator would be used. In this example, we have a pattern of eight holes. Rather than dimensioning the size of each hole, only one hole is dimensioned. An 8X is placed in front of the dimension to indicate that this dimension applies to all eight holes.
Figure 1: Holes Dimensioned Using the #X Designator to Indicate Multiple Identical Features
Additional examples of the #X designator in use are shown in Figure 2. Examples for identical radii, chamfers, and surfaces are shown. Notice that the #X designator is associated with a feature control frame in the multiple identical surfaces example. In this case, each of the three surfaces are separate specifications and would be separate line items on an inspection report – each surface would have its own reported parallelism error. If the intent is to control the three surfaces as a continuous feature, then the continuous feature symbol must be used.
Figure 2: Multiple Identical Chamfers, Radii, and Surfaces Dimensioned Using the #X Designator
Overwhelmed by the Complexity of GD&T?
Learn GD&T at your own pace and apply it with confidence in the real world.Get Your GD&T Training