What is the frame and casing made of? I have a Db 100 and it has a plastic case and it twists a lot & throws or breaks the blade. I've ordered parts & blades several times. Finally had to quit using it because of the way it is cheaply built. If it was a stronger material like metal casing, it would wonderful. I loved that db100. It was amazing to use. But the material is cheap and Twisted too much. Always repairing and after a few months it would break the blade or throw it off