In recent years, the proliferation of low cost digital fabrication devices has greatly reduced the barrier to entry of making. However, these tools expose narrow digital interfaces which limit the ways in which users can design and prototype with them. In particular, the 'click-to-print' workflow of tools like 3D-printers lose many of the tangible and embodied features of physical making. In this thesis, we reimagine the way computation can mediate the digital design and prototyping of physical objects. We present Turn-by-WiAR, a novel smart tool that uses augmented reality (AR) and drive-by-wire haptics to combine the design metaphors of Computer-Aided Design (CAD) with the tacit knowledge of hands-on making. In embedding the capabilities of a manual fabrication tool with computer-generated visual, sonic, and haptic augmentations, we design a number of new interactions that promote a more embodied prototyping process. An evaluation with novice practitioners shows how our tool de-risks exploration, boosts creativity, foregrounds material properties and machine tendencies, and increases precision. Finally, we envision how such kinds of smart tools might enable non co-located real-time collaborative design, in-situ creation, and other novel fabrication workflows.