Singer has a really good book that shows how to balance the tensions. Usually, it's tensions that are off. I know I've written a novel on sergers in a couple of threads. I'll see if I can find one or two of them.
Edit: Here's one:
http://www.quiltingboard.com/vintage...ml#post6572899
Last edited by ArchaicArcane; 04-17-2015 at 08:41 PM.