I agree with other reviewers that this mandoline is poorly designed. I think there must also be quality-control problems at the factory. That is the only explanation I can come up with for the range of comments about this product. I was able to use the waffle blade just fine, but not the straight blade. The waffle blade should be technically harder to use, so I don't think user error can explain away all the problems reported.The saying that a sharp knife is safer than a dull one seems like a contradiction. We know however that when you have to use excessive force to cut something bad things happen. The unit I received came with a dull straight blade made of metal that is difficult to sharpen by hand and doesn't fit in my knife sharpening station. Because I had to use a lot of force to try to get potatoes through the blade area the plastic around the blade is now coming apart.I suggest buying a V-slicer instead.