A worn part arrives with no drawing. That is where the work starts. It goes under the video measuring machine first, where every dimension is captured optically at magnification, including the features that calipers cannot reach. Those measurements become a controlled CAD drawing, and that drawing becomes the part.
The original tells us the geometry. It does not tell us why it failed. That part is engineering judgement: material grade, heat treatment, surface finish, and where to add life without changing fit.
Reverse engineering done properly is not copying. It is understanding.
