The only thing I didn't like about this device was that it was desgined to work best when the file is held 90 degrees to the bar. I like to put a 10 degree slant on my full chisel chain. When this is done using the Pferd, the rail that rides on the adjacent tooth tends to start to wear it down a bit as it is riding on the outside edge of the top plate rather than across the top plate proper. Once the tooth is taken back far enough, this may affect the edge one is able to put on the tooth. Otherwise, it works fine. This is probably clear as mud.