One of last weeks class students brought a tube type Anderson scraper with a carbide blade we ground and lapped to a 60 deg. radius and he did a good job flaking with it. He didn't like it as a hand scraper and preferred the German style I recommend.So I learned how to bump flake yesterday and I want to know what rake angle I should use. Currently it is a 120mm radius as recommended and a 5 deg negative rake on an Anderson scraper since is too stiff to be a scraper