The term Blueprinting was from the olden days. Where the draftsman drew the "blueprints of his design. With the preferred clearences, mass, dimensions etc. However mass production and machining techniques in large volume ment that there were large variations between the upper and lower tolerances. Blueprinting would select or adjust components to be between upper and lower limits as per the blueprint. However modern tooling and machining can produce vastly more accurate and consistent parts. So there is less need for Blueprinting.
