This paper introduces a haptic data reduction and transmission technique to reduce the packet rate in six degree-of-freedom (6-DoF) haptic-enabled telementoring systems. The presented method relies on the limitations of human haptic perception (i.e. the Just Noticeable Differences) with respect to a user's hand position and orientation in order to reduce the number of packets transmitted without compromising transparency. A haptic prediction model is exploited to further reduce the amount of haptic packets transmitted, and to improve the reconstruction of data samples on the receiver side. Several distance metrics are also discussed to evaluate the acuity of human haptic perception when data reduction is performed in 6-DoF settings. Psychophysical experiments validate the effectiveness of the suggested algorithm as great haptic data reduction is achieved (up to 96%), while preserving the overall quality of the telementoring environment.