The rotary sharpener with the knob on top that you turn is the Orbital sharpener. It does work but a sharpened blade is never quite as good or lasts as long as a new one. I find if I sharpen it before it has any nicks or is totally dull then it is maybe lasts 3/4's of a new one. A second sharpening will last 1/2 as long and often I can get a third sharpening after which I usually discard them. It will not remove large nicks and care must be taken when getting the blade in place not to cut yourself. The sharpeners are not cheap ($37 Canadian) plus 13% sales tax but eventually it will pay for itself and new parts (the little grinding wheels) are available. I buy blades, a dozen at a time when they are on sale at Len's Mills (a large discount fabric/craft/linens/lots of other interesting stuff type of store once or twice a year.