Datum | Datum Feature | Datum Feature Simulator in GD&T

👉 As per ASME Y14.5 – 2018, “Datums” are theoretical, whereas, “Datum features” are real and are part of the manufactured component.

👉 “Datums features” are used to associate datums on the engineering drawings.

👉 But, we can’t measure the dimensions from the datum (as it is only theoretical) and that’s why we need “Datum Feature Simulator”.

👉 “Datum Feature simulator” is a close to perfect surface like Surface Plate or Gage surface which is used for “Simulated Datum”.

👉 “Simulated Datums” are achieved by touching the part at the high points on the “Datum Feature Simulator”.

👉 “Simulated Datum” is used to measure the actual dimensions on the manufactured components.