Advances in the machining of titanium workpieces are of special relevance to the aerospace and navy industries. Titanium is a notoriously difficult-to-machine material. Recent research indicates that the amount of oxygen in the surrounding air has a major effect on its wear process. Oxygen removal from the reduces tool wear and, thus, improves the tool's surface finish over time. However, the precise process through which oxygen causes wear is still a matter of discussion. In this research, we examine simulations of the cutting process of single-crystalline hcp-titanium on the {0001} plane with and without an oxide layer. For the purpose of revealing size effects, reference simulations with pure titanium crystals of various sizes are undertaken. Compared to the bulk crystal material, the oxygen layer exhibits a more brittle behavior, which effects the nanoscale creation of the chip. Instead of creating a smooth chip, as is the case with pure titanium, the simulation with an oxide layer reveals no chip development at all during the measured time scale. These elevated temperatures may increase the interdiffusion between the workpiece and the tool, hence amplifying the prevalent tool wear process.