Open tolerance for drawing
In the title box of drawing sheet we mention open tolerance, can any one help me in understanding this. Because I have seen some times some company gives very lose tolerance in title box and specify required tolerane with dimension but some places i have seen that we give tight tolerance in title box (which is valid for all drawings) and control tolerance through decimal places. So is there any standard for this and what is the right method ? Most of the components with which i deal is plastic components and unit which we use is metric.