It does an excellent job, although I used it to sand a pipe that had grooves on the inside due to turning, it smoothed it out well even though that's not its intended purpose. However, the stones didn't last long and at the end of the job they were worn out and need replacement. This is probably due to the quite "rough" surface of the pipe, maybe for the job I wanted, I needed coarser stones (if they exist, I don't know), and after the surface was leveled, I would use these stones for sanding and not for metal removal.