Disclaimer: This post is for informational purposes. Always refer to the latest official DIN ISO 13715 standard document for absolute compliance.
If you have ever looked at a technical drawing and wondered, "Is that edge supposed to be sharp? How sharp is 'sharp'?" — you are not alone.
Here is what the symbols mean:
Simply put: It tells the machinist how to treat the "leftover" edges—those small intersections between two surfaces where no specific radius or chamfer is called out.
![Example symbol structure: A triangle-like figure with a line pointing to the edge, plus a numeric value.] din iso 13715
In the world of precision manufacturing, assuming an edge is sharp can lead to burrs, injuries, and assembly issues. Conversely, assuming an edge is broken (chamfered or rounded) without a specification can lead to unnecessary machining costs.
Let’s break down what it is, why it matters, and how to read its symbols. Officially titled "Technical product documentation — Indications for undefined edges," DIN ISO 13715 specifies how to indicate the permissible condition of edges that are not explicitly dimensioned elsewhere on the drawing. Disclaimer: This post is for informational purposes
Enter . This standard is the universal language for defining the condition of undefined edges on technical drawings.