Standard solution: choice of tolerance for a dimension
A fixed way of thinking that keeps tolerances realistic
It is easy to set tolerances either far too tight (expensive and unnecessary) or far too loose (the parts do not fit). Follow the same sequence every time, so the choice becomes deliberate instead of random.
§1. What is the target's function?
- 01Should the measurement ensure that two parts fit together?
- 02Should something be able to move slide or rotate?
- 03Or is it just a goal that has no critical function?
§2. Choose level
- 01Non-critical dimension: let it be covered by the general tolerance in the drawing header.
- 02Function-determined dimension: give it a specific tolerance that corresponds to the function.
- 03Fit size: choose a fit (clearance, transition or press) based on what the connection should be able to do.
§3. Check against the whole
- 01Does the measurement lie in a chain where deviations can accumulate? Consider a common reference.
- 02Is a tight tolerance really necessary or can it be loosened without the function suffering?
- 03Can the part be made within the tolerance you have chosen?