Originally Posted by
skjack
I had trouble with was superior rainbow thread so just don't use it.
Superior Rainbow and its "sister" thread in solids called Highlights were known problematic threads as in very weak and prone to breaking and shredding. Superior discontinued both for a period of time but now they have brought the Rainbows back. But back around 2011-12 time frame both threads were causing untold amounts of trouble for countless longarmers. Maybe they changed something in their new rainbows to solve the issue. I have successfully gotten the problem years to run with very low tension settings in both top and bobbin. So if you are stuck with some cones of it you can try running it at low tension and see if that helps you.