The strongest mechanisms that contribute to machining chatter are regeneration and mode coupling. Special designs of milling cutters have evolved with the aim to increase stability against chatter by disturbing the regeneration mechanism. However, in the case of slender end mills, the mode coupling remains most active. In this work, a new approach is presented where a design change of the cutter is suggested to weaken the mode coupling mechanism. Time domain simulation of the development of chatter showed that using this approach significant increase in stability could be achieved. Cutting tests of aluminum with the modified end mills confirmed simulation results.