The Key Of Notes On Drawing

Sometimes, the most important information on a drawing isn't the datums or the dimensions. It's the words.

We expend most of our effort perfecting callouts and tolerances, and rightfully so. A good drawing should tell a story, and datums, dimensions, tolerances, those are some of the most important storytelling devices. GD&T gives us a common vocabulary that transcends language barriers.

Later, we circle back to the notes… maybe slap some boilerplate  'catch all' notes for good measure.

But sometimes, that's not enough.

Good drawing notes provide context, helping to explain the details beyond the numbers - surface prep, coating details, assembly order, inspection assumptions, and the countless small decisions that don’t fit cleanly into a tolerance frame.

I've seen perfectly dimensioned drawings lead to incorrect parts, sometimes the result of a single unwritten assumption that lived only in the designer's head.

A good drawing doesn't just describe shape. It communicates expectation.

Dimensions control geometry. Notes aid with interpretation.