TS ISO 10579

TS ISO 10579 addresses the rules for dimensioning and tolerancing non-rigid parts on technical drawings, with particular attention to cases where some feature restraint is needed during verification of the specified dimensions and tolerances. In drafting practice, the key issue is that a part may behave differently in free state and during inspection, when it is supported or constrained.

How non-rigid parts are understood in technical drawing

In general engineering terms, non-rigid parts may be thin-walled, flexible, elastic, or otherwise able to change shape under their own weight or under clamping forces. For such parts, a drawing dimension is not fully self-explanatory unless the inspection condition is also understood. The purpose of this standard is to provide rules for expressing dimensions and tolerances consistently when verification requires restraint of certain features.

Why the distinction matters

• A part’s free-state geometry may differ from its geometry under inspection restraint.
• Clear definition reduces ambiguity in dimensional checking.
• For non-rigid components, conformance depends not only on the nominal size but also on the verification condition.
• The standard supports a clearer technical language for dimensioning and tolerancing on drawings.

This edition was published as TS ISO 10579:1999 and was later withdrawn; even so, it remains useful as a reference for understanding the drawing logic used for non-rigid components. More broadly, documents of this kind do not create a product design by themselves; they define how the part is to be represented and how a specific inspection distinction should be handled.