most of the logos on frame parts are cast in. However, you can use a pantograph. I have seen some that appear to be done on a 4 axis cnc, but I have no way of knowing if that is true. I'm sure there are also 4 axis pantographs. I guess it depends on your definition of 'diy', I don't know of any low-cost methods of engraving. Obviously, many things can be done by drilling/filing.