[Urbane Guerrilla]

Mandolines are called that because you're sort of strumming up and down the thing. And yes, razor sharp blades are a must or it flat refuses to work. That means don't use the cheapest stainless alloy you can get your suppliers to supply, but instead the pricier alloy that will actually perform. There is such a thing as high carbon stainless steel. It's often called surgical stainless, but within that category are alloys that are better for edgeholding than some others.