If you’ve ever seen cryptic symbols next to a 45° chamfer or a sharp edge on a drawing and wondered what they mean, this guide is for you. ISO 13715: Technical product documentation — Indications of undefined edges is an international standard that defines the rules for indicating the state of edges that are not explicitly dimensioned in a technical drawing.
![Symbol description: An isosceles triangle (similar to a surface roughness symbol but with a rounded tip) with numbers around it.] iso13715
In simple terms: It tells the manufacturer what to do with the edges of a part—whether to leave them sharp, break them with a chamfer, or round them—without cluttering the drawing with redundant dimensions. If you’ve ever seen cryptic symbols next to
In the world of technical drawings and manufacturing precision, every micron counts. However, not every edge on a workpiece can be perfectly defined. Enter ISO 13715 , an often-underestimated but critical international standard that governs how to specify the condition of undefined edges. In the world of technical drawings and manufacturing
The standard was previously known as , with the latest revision being ISO 13715:2017 . Why Do We Need It? Without ISO 13715, engineers would have to individually dimension every single edge on a complex part. Imagine a bracket with 50 edges—each requiring a "0.5 x 45°" callout. This is not only time-consuming but also makes drawings unreadable.