This paper presents a model for describing machine tools based on the STEP standard AP239 as a neutral format for communicating information throughout production development and operation. The machine model is further defined at a reference data level, where concepts regarding machine tools are defined from four main viewpoints: process planning, investment process, factory planning and operation/improvement. The concept models extend the standard and define the specific machine tool information. The utilization of the machine model is exemplified in a use case.