Industrial robots have become a key technology across sectors for their cost efficiency availability and multi-axis flexibility, but their application in wood machining remains limited, with no studies on the quality of solid wood machined by robots. Achieving satisfactory surface finishes in wood machining is complex due to grain direction, often requiring sanding. While many sanding processes are automated, manual operations dominate for complex shapes. This study aims to evaluate the capability of a 6-axis robot in wood machining by comparing its dimensional, geometrical, and surface quality to the CNC router, the industry benchmark. It also aims to investigate the relationship between the roughness indicators of parts machined with different grain direction and signals measured during machining, determining the parameters correlated with the wood surface quality, and establish threshold values for roughness indicators beyond which sanding is required, allowing the identification of areas requiring finishing. To assess the robot’s capability, oak, and fir samples were machined under identical conditions in six robot positions and with a CNC router, followed by dimensional, geometrical, and surface quality evaluations. The results show that a poly-articulated robot produces sufficient dimensional and geometrical quality for various wood applications, as well as surface quality comparable to that achieved by CNC router.