Semi-automated timber fabrication tasks demand the expertise and dexterity of human workers in addition to the use of automated robotic systems. In this paper, we introduce a human-robot collaborative system based on Augmented Reality (AR). To assess our approach, we conducted an exploratory user study on a head-mounted display (HMD) interface for task sharing between humans and an industrial robotic platform (N=16). Instead of screen-based interfaces, HMDs allowed users to receive information in-situ, regardless of their location in the workspace and the need to use their hands to handle tools or carry out tasks. We analyzed the resulting open-ended, qualitative user feedback as well as the quantitative user experience data. From the results, we derived challenges to tackle in future implementations and questions that need to be investigated to improve AR-based HRI in fabrication scenarios. The results also suggest that some aspects of human-robot interaction, like communication and trust, are more prominent when implementing a non-dyadic scenario and dealing with larger robots. The study is intended as a prequel to future work into AR-based collaboration between multiple humans and industrial robots.