Co-located haptic feedback in mixed and augmented reality environments can improve realism and user performance, but it also requires careful system design and calibration. In this poster, we determine the thresholds for perceiving co-location errors through two psychophysics experiments in a typical fine-motor manipulation task. In these experiments we simulate the two fundamental ways of implementing VHAR systems: first, attaching a real tool; second, augmenting a virtual tool. We determined the just-noticeable co-location errors for position and orientation in both experiments and found that users are significantly more sensitive to co-location errors with virtual tools. Our overall findings are useful for designing visuo-haptic augmented reality workspaces and calibration procedures.