A complete dynamic modeling on task space for a 6 DOF Gough-Stewart platform type of CNC machine is derived. The rotation terms of the legs are included for its inertia effect cannot be negligible in the machine tool applications. Also its formulation derived by means of Euler-Lagrange method is convenient for designing the adaptive control law. The average-type force model for planar end-milling process is derived. A composite adaptive control scheme is developed by use of filtering dynamics technique. An appropriate weighting is designed in the parameter adaptation law that is useful for estimating the selected important cutting parameters in particular in the light milling process. Experimental results verify the proposed adaptive control scheme can achieve good tracking performance.