Try Ebay
I cut a bunch of SoJar, which is a thin film for heat transfer that they sell here in the USA. I use the 60 degree cutters on my SC-545 and they work much better than the 45s. I was able to buy them from a guy on Ebay, they were Carbide and I have been fairly pleased, as the guy sells them in bunches of ten, but you can select what mixture of angles you want. I think his web site is seikitech.com. Hope that helps.
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Hogwild Imprints, Inc.
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