is more than just a drawing note—it is a language of compromise between perfect design and real-world welding. By understanding that "B" stands for Medium tolerances and "F" typically implies general fabrication , you can set realistic expectations for cost, quality, and delivery.
Engineers indicate this standard in the "General Tolerances" block of a technical drawing (e.g., "General Tolerance: EN ISO 13920-BF") to avoid labeling every single dimension with a specific tolerance. en iso 13920-bf
: Represents the tolerance class for linear and angular dimensions . Class B is considered "medium" or "customary workshop accuracy". is more than just a drawing note—it is
A very specific topic!
If you encounter :