A series of simple mechanical tests on single crystal diamond, diamond styli and diamond finishing tools has shown that frictional force, surface cracking and strength behaviour under simulated wear conditions can be improved as the result of N and Bion implantation at room temperature. Scratch tests on a polished macroscopic diamond of (111) planar orientation submitted to a total dose of 9.1015 N ions/cm2 revealed that a slight reduction in friction force occurred during dry sliding over the implanted region. Nitrogen implanted diamond gramophone styli held against a slowly rotating polished TiC disc under light load were found to significantly outlast unimplanted or carbon implanted samples, which generally failed abruptly on contact. In a third series of experiments, diamond tipped finishing tools used for high speed machining operationson acrylic plastic were implanted with N, B, and C ions to similar doses, all below 1016 per cm2. Nitrogen and boron implantations were found to improve the cutting life and quality of cut by as much as a factor 5, whereas carbon ions were much less effective.