72 Show real values Write the true size of the part, even when the photo or drawing is scaled. Do not repeat the same dimension twice.
Keep dimensions readable Place dimension lines outside the contour when possible. Put smaller dimensions closer to the part and larger ones farther away.
Use extension lines cleanly Extension lines should lead from the measured element and pass a little beyond the arrow tips. Avoid crossing dimension lines.
R Ø Use Ø and R correctly Use Ø for complete round features and R for radii or arcs. Put the sign before the number.
note Use callouts for notes When a number does not fit on the dimension line, place it on a shelf with a leader arrow. Keep the text clear of other lines.
