This research aims to develop a portable haptic master hand with 20 degrees of freedom (DOF). Master hands are used as haptic interfaces in master-slave systems. A master-slave system consists of a haptic interface that communicates with a virtual world or an end-effector for tele-operation, such as a robot hand. The thumb and fingers are usually modeled as a serial linkage mechanism with 4 DOF. So far, no 20 DOF master hands are developed that can exert perpendicular forces on the finger phalanges during the complete flexion and extension motion. In this paper, the design and development of a portable 4 DOF haptic interface for the index finger is presented. The concept utilizes a mechanical tape brake at the rolling-link mechanism (RLM) for passive force feedback. The systematic Pahl and Beitz design approach is used as an iterative design method. Important design requirements are; perpendicular forces on the finger phalanges, low friction mechanism, easy to control, no backlash, high backdrivability and lightweight.