This study consisted in investigating parameters that significantly influence the spray efficiency of minimum quantity lubrication in a milling tool with inner channels. An initial experimental approach was used to estimate the oil mist consumption and outlet particle velocities with different inlet pressures, for different shapes of inner channels, without rotation (static part). An experimental versus simulation comparison was undertaken between outlet velocities as a function of inlet pressure. The Reynolds-averaged Navier–Stokes model with the Lagrangian multiphase models was validated by comparing experimental and numerical outlet velocities for different inlet pressures. A numerical rotating tool with inner channels was used with the validated model in the second numerical simulation to analyze the influences of inlet conditions (inlet pressure) based on the tool shape and the rotation velocity, in a dynamic approach. The main objective of the oil mist is to reach the cutting edge (qualifying the minimum quantity lubrication spray efficiency) depending on the inlet conditions (inlet pressures) and the machining configurations (rotation velocities) by analyzing the streamlines of the oil mist particles. The study pointed out the tool design effect combined with its rotation velocity on the oil mist capability to reach the cutting edge. This study offered a trend of parameter sets to provide correct inlet parameters based on machining configurations. At high rotation speed, the inlet pressures needed to be high enough to counter the aerodynamic effects occurred by the tool design.