I have the sapphire 830 and they told me it 'didn't like coats and clark thread' and I said that is bull**** I have had my machine a year and now am using some thread that i had before I purceded it which just happens to be coats and clark. and (knock on wood) recently I havent had much trouble. actually one of the 'salespersons' told me that coats and clark was not winding their thread differently and it shoulding be as much of a problem. I say this shouldn't be a problem at all for any machine esp when you pay over $1000 for it ....good luck