En Iso 13920-bf ((free)) -

This is the tolerance class for lengths (like the distance between two plates) and angles. Class

A recurring question in engineering forums is whether a note like "ISO 13920-BF" is sufficient on its own. While the standard provides the tolerance values, some engineers argue for more explicit controls using datum references, especially for critical features. For complex structures, special provisions for individual dimensions may be necessary. The standard itself acknowledges that general tolerances are for dimensions without individual tolerance specifications. If a drawing includes linear and angular dimensions without individually indicated tolerances, it is considered incomplete if there is no reference to general tolerances. Therefore, including "EN ISO 13920-BF" in the title block is the correct method to complete the drawing and provide the manufacturer with the required tolerance information. en iso 13920-bf

The selection of a tolerance class has a direct impact on manufacturing cost, complexity, and risk. The "BF" combination is widely used because it represents a practical balance between precision and economic reality. This is the tolerance class for lengths (like

For the Quality Control (QC) department, this standard provides a black-and-white rulebook. If a part is out of tolerance, it is rejected. If it is within the range, it is accepted. There is no room for subjective debate. Therefore, including "EN ISO 13920-BF" in the title

The standard defines various types of tolerances and deviations that are relevant to welded constructions, including: