Comparison of the Frequency Response Functions experimentally measured at the tool tip for a milling machine structure, and two end mills with an overhang-diameter relation of 4:1 and 7:1:
The modal frequencies of the structure are below 100Hz while the frequencies of the tools are higher than 400Hz. The tools are dinamically more flexible than the structure of the machine. What is more, the difference in the tools produced by the different overhang-diameter can be seen.