This review is my first impression and I have given it a 4 for the following reason. During the initial setup, the tool starts and the next time it is started, it stops. Decided to see if the problem could be solved. I lubricated and started the device, it got better, less stalling, but still unsatisfactory. Next I checked the valve assembly by removing it from the grinder. I then lubricated the valve and tappet with plenty of oil. Collected again. I started it and saw that the extra file came out of the tools opening. I drove it for a while, turned it on and stopped it. Did this for about 10 minutes. Everything is fine now, it won't start. Seems like it needed some extra lubrication and break-in time to get it working. The manufacturer should operate the device more carefully. There would be fewer of them in the ratings.