I have a fiskars 45 mm. one and I don't know if it is true for other names brands but I buy my blades at Harbor Freight in the carpet layers section. They fit and if you are lucky on sale you get 2 blades for less than a dollar in one package and if you are not lucky you get 2 blades for a little over a dollar. They are throw away at that price and a new one for almost every project!!!!!!!!!! I love it. I stock up and always have at least a dozen on hand. It is worth a try in other brands as well.