The center of the indicated datum feature becomes the datum axis or datum center plane. The dimension line of a datum feature and the datum are indicated apart from each other. Click to place the object in the drawing, and. The center of the indicated datum feature becomes the datum axis or datum center plane. DesignSeries00115.png Datum Feature Symbol Click the Datum Feature Symbol tool from the Dims/Notes tool set. Annotating an Axis or Center PlaneĪ datum feature is indicated by combining the dimension line and datum. Final Drawing with datum target locations table Lastly, we should define the locations of these datum target areas with respect to a defined coordinate system (Figure 4). To express the design intention with strict accuracy, pay attention to the position where you indicate the datum. The position of the datum symbol on the drawing is also relevant to the target area. The letters indicating the datums are always oriented to the direction the reader looks at the drawing. Datum symbols use either a white or black triangle. Datum Drawing is an exhibition that explores the use of datum in drawing as an architectural or spatial point of reference. Drawing Indications of Datum Featuresĭatums are indicated using the following symbols (datum symbols). Therefore, a surface plate, gauge, or mandrel, which has a more precise surface, must come into contact as a simulated datum.Į Surface plate, gauge, mandrel, etc. The surface of a part indicated as a datum is not an exact shape. Datum System A group of datums created by combining more than one individual datum in order to use it as a reference for toleranced features. As with all the Modules in this package, ICSM is trying to explain often. As Datums is a ‘jargon rich’ discipline it is recommended that you first read Datums - The Basics first. Simulated Datum Feature An actual surface with sufficiently precise shape that comes into contact with a datum feature and is used for establishing a datum (e.g. The content of these two is very similar, but as their titles suggest, they supply different levels of information. Datum Feature A real (non-ideal) integral feature of a target used for establishing a datum (e.g. Multiple datums can also be combined to make a datum system that specifies a feature. A datum is a plane, a straight line, or a point that is used as a reference when processing a material or measuring the dimensions of a target.Ī datum is defined as follows in the ISO standard: ISO 5459：2011 “One or more situation features of one or more features associated with one or more real integral features selected to define the location or orientation, or both, of a tolerance zone or an ideal feature representing for instance a virtual condition.” Types of Datumsĭatums are established using datum features and simulated datum features.

Drawing datum