I have a MC 7500 that uses the Guitterman fine and the cones fine it will not use the Coats and Clarks cheapy type at all it breaks every few inches. But the cones work great and are cheap to use. I just got a MC 6600 Professional and have not used it enough to know if it works on it but I will stick with my cones and Guitterman. There is another brand that starts with a M and it works fine on my old one too. Yes the cheapy stuff works fine on my 1975 Kenmore but Janome spits it out.
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