Because of the simultaneous requirements rule stated in the Y14.5 Standards (section 4.5.12 in 1994, 4.19 in 2009, and 7.19 in 2018), if features are controlled relative to the same datum reference frame (same datums, same precedence, same modifiers), the features are considered to be a pattern. Both drawings shown below indicate that the two keyseats are a pattern and must be located as shown.
The keyseats are considered to be a pattern. Their location and orientation are controlled by the position callout(s).
In order to unlock the orientation of the two keyseats to one another, a note indicating separate requirements must be stated.
In this example, the orientation of the keyseats is unimportant.
This tip is in accordance with ASME Y14.5M-1994, Y14.5-2009 and Y14.5-2018.
This tip was originally released in January 2000.