This part of ISO/TS 13399 specifies a concept for the design of tool items, limited to solid (non-indexable) end mills, with the usage of the related properties and domains of values.This part of ISO/TS 13399 specifies a common way of design simplified models that contain the following:— definitions and identifications of the design features of solid (non-indexable) end mills, with a link to the properties used;— definitions and identifications of the internal structure of the 3D model that represents features and properties of solid (non-indexable) end mills.The following are outside the scope of this part of ISO/TS 13399:— applications where these standard data may be stored or referenced;— creation and exchange of simplified 3D models for cutting tools;— creation and exchange of simplified 3D models for cutting items;— creation and exchange of simplified 3D models for other tool items not being described in the scope of this part of ISO/TS 13399;— creation and exchange of simplified 3D models for adaptive items;— creation and exchange of simplified 3D models for assembly items and auxiliary items.