If the Drawing Doesn’t Use GD&T--Run (#249)
(In accordance with the ASME Y14.5-2009 standard)
PDF is Available with GD&T Reference Center Subscription.
I am often asked to explain the meaning of a drawing that doesn’t use GD&T. The problem is that too many assumptions must be made to guess at what the folks who made the drawing really mean. Here is a redraw of a drawing I recently commented on. The second drawing includes datums and geometric tolerances. The only difference is that the first drawing is not supported by any standard. The second drawing has one clear meaning. It took 8 mouse clicks and a few keyboard strokes to turn a meaningless piece of paper into an engineering drawing with fully defined geometry. It is inexcusable for someone to create a drawing like the first one and commit resources to produce a part. Drawings with GD&T are today’s "blue prints". If you are responsible for the design, manufacture or quality of mechanical parts, you should know how to read a print. Sadly, most colleges and some trade schools do not teach today’s print reading.
It takes about 24 hours to learn this life time career skill. If you do not have time to learn how to read prints, you might want to consider the restaurant business. For those of you who understand GD&T, please, stop tolerating bad drawings!
