Part Modeling > Datum Features > Datum Axes > To Create a Datum Axis by Selecting a Revolved Surface and a Datum Point or Vertex
  
To Create a Datum Axis by Selecting a Revolved Surface and a Datum Point or Vertex
1. Click Model > Axis. The Datum Axis dialog box opens, with the References collector active.
2. Select a datum point depending on your design intent for the axis placement:
To create an axis that is normal to the revolved surface, select a datum point that is located on the surface.
1. Datum point on surface
2. Surface
3. Datum axis normal to revolved surface
To create an axis normal to the axis of revolution of the revolved surface, select a datum point that is not located on the revolved surface.
1. Datum point
2. Surface
3. Axis of revolution inferred from the revolved surface
4. Datum axis is normal to the axis of revolution
3. In the References collector, next to the datum point, select Through as the constraint.
4. Hold down the CTRL key while you select the revolved surface.
5. In the References collector, next to the revolved surface, select Normal as the constraint.
6. Click OK.