• 1-888-TEC-EASE
  • Outside USA: 1-716-785-6015
Free Tec-Ease Mug GD&T Textbooks GD&T Training GD&T Public Seminars GD&T Computer Based Training GD&T Reference Material
Watch the Placement of Datum Identification Symbols and the Feature Control Frames for Straightness, Perpendicularity, Parallelism and Angularity
(In accordance with Y14.5M-1994 standard)

PDF of this Tip

When applying the above to features of size, the placement of the symbol or callout can greatly change the meaning. If the symbol or control is associated with the size dimension, the feature’s axis or center plane is being identified or controlled. If the symbol or control is associated with the surface of the feature of size, it is identifying or controlling the surface - not the axis or center plane. In this example both the datum feature symbol and the perpendicularity apply to the feature’s center plane. Notice that there are two center planes.

In the second example, both the datum feature symbol and the perpendicularity apply to the right surface of the slot.

Back to Tips Tip added Aug 1998