Originally Posted by Prism99
Needle size does matter. Superior Threads recommends a #90 topstitching needle. Here is their recommendations page for King Tut:
http://www.superiorthreads.com/shop/...t/description/
If they're recommending loose bobbin tension with Masterpiece or So Fine, I would think it has to be even more loose if you are using King Tut in the bobbin as well as on top, as it would be a much thicker thread.
I use King Tut on my Pfaff's, Juki and vintage Singers and never have any problems. I do believe you don't have your tension adjusted properly. You can also call Bob (if he's there) at Superior or speak to someone there and ask for guidance.
King Tut is my absolutely favorite thread. If you go to their website www.superiorthreads.com and browse the website they have all kinds of instructions for the threads they sell, preferred needle size and many other helpful hints. They also send out a newsletter which is well worth getting.