Knowledge of machine tool drive dynamics is imperative to achieve optimal, robust performance with precision and productivity. Modelling ball-screw drives is vital in order to have a feasible insight into the structural vibration modes of the mechanical assembly, which typically limits the bandwidth of developed controllers. In this paper, an output-only modal identification, Operational Modal Analysis (OMA), is used to validate a ball-screw feed drive model while running without cutting. The experimental results indicate that the identified parameters on the running state are different from those of static state and mathematical modelling. Furthermore, it is possible to validate and calibrate dynamic models using OMA by measuring the table structure responses without knowing the excitation input.