It is possible to increase the machined workpiece accuracy and productivity during turn-milling operation by modeling the cutting forces and thermally induced deformations on cutting tool. In order to achieve this task, the main objective of this study is to determine the thermally induced deformations on tool during turnmilling operation and reduce them by applying pressurized cooled air. In this study cutting forces, tool temperatures and deformations modelled by FEM coupled with analytical and mechanistic expressions are compared to those obtained by some series of experiments. It was shown in the study that those deformations could be upto 40% of the depth of cut during fine turn-milling. However they can be reduced by means of cooled air by 65%. Furthermore, tool wear and surface roughness values of machined workpiece were also measured and as it is stated in the paper that the surface values in fine turn-milling operation could be as good as they are in grinding operation.