I have had this machine for some time and it is difficult to remember how many times you have put each blade through, you also have to make sure that you pull the knife through at the correct timing rate. I have had problems with knifes "shuddering" and it isn't really that good for the cheaper knives. My good knives all come up reasonably sharp - but certainly not razor sharp, but the cheaper ones are just "not as blunt". I have had better results with hand-held sharpening devices.

just not as good as it should be