I have broken my old rotary cutter and need to purchase a new one. I am planning on purchasing and Olfa. Are the blades from Fiskars and Olfa (or from other brands) interchangable? I have 4 news blades from my Fiskars and I don't want to discard them, but I don't want to purchase NEW blades for my Olfa if the old ones will work. Any help on this would be sincerely appreicated.