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Robots in force control mode often become unstable during contact with stiff environments, due mainly to the high gain nature of wrist force-sensor feedback. To achieve stable force control, we propose an essential reliance on fast open-loop joint torque control, and relegate tip force sensor feedback to a slow loop to maintain accuracy. Dynamic stability is analyzed with a simple model of the robot and its environment. The analyses are verified by single-link experiments on the MIT Serial Link Direct Drive Arm.