1 week hire of a tree stump grinder. Equipment as specified. Delivery and Pick up went smoothly. I was charged a sharpening fee but the grinders "teeth" were blunt on arrival and looked like the worn shape that the instructions suggested would damage the machine. No resharpening information provided. Even with gentle use the equipment failed after grinding 5 small stumps. The internal drive mechanism had disintegrated. Returned and repaired quickly, but teeth still blunt. I reset the teeth by rotating them to present the more sharp edge to the front. This improved the cutting power significantly. The machine worked well for the remaining stumps.