These shredders are excellent when working with flat leather hard surfaces. For years you could find a tool like this at the hardware store. This rasp was designed to be used on wood. Clay people, sculptors and auto-body repairmen discovered how well the blade worked on other materials i.e. clay.
The problem was the handle design that would trap clay and get clogged up. However, with this new open blade shape that problem is solved and on top of that they come with a comfortable ergonomic grip. An added benefit is the tool mark, it leaves a handsome textured surface in the clay.