A shadow graph and supporting data collection equipment or overlays can help with some face quality inspections. The support equipment can give distances between points along with radii and angles. The overlay will show go/no-go on radii accurate to ± .002 at 20x. The angles can be measured to
± 30' with an overlay. This is sufficient in some cases but is always subject to interpretation by the inspector and clarity of the shape being measured.

Data collection support equipment with several options of what and how to measure.       Shadow of part to be inspected

Surface flatness can be checked by use of a height gage. If an angle is needed the drop given per distance traverse will help in determining the angle of the face.

sin of angle needed = total drop ÷ total travel of drop

With this inspection, the interpretation can easily distort the findings. The consistency and quality of the face flatness or angle is near impossible to determine with this method.
Data collection support equipment with several options of what and how to measure.   Shadow part to be inspected.