How to find a good sweet potato fry cutter? I am looking to make my own sweet potato fries, however sweet potatoes are harder to cut than regular potatoes.

Even more expensive cutters such as the Nemco N554503 fry cutter are not recommended for cutting sweet potatoes. 

Does anyone know what makes a cutter suitable for sweet potato fries?
I have the Progressive International Jumbo Potato Cutter and it works well for sweet potato fries. The product spec for them lists "Yams" which are sometimes what sweet potatoes are called in the U.S. (technically, yes, yams are different but real yams are not often available in the U.S.). The LEM Products Commercial French Fry Cutter specifically lists sweet potatoes:


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