I have the exact machine and Yes! this happened to me. I left a spool of thread on the spindle to fill bobbins. I noticed that thread on the spool was winding and I thought that's odd. I realized it was going right to the fly wheel. It was a full spool of Aurifil and it was half gone. I started unwinding the thread but after 20 min. I was bored with that taking it slow so the thread wouldn't break. I took the housing off my machine and cut the rest off the shaft. It wasn't hard to get the thread out. I'm glad it wrapped in a spot that didn't cause the machine to bog down. Also the at little space where the reverse lever is? Well a pin got in that hole somehow and fell to the bottom and stopped the gear from turning. I took the machine apart and there was the yellow flat head pin stuck right in the gear. I took it out and the machine worked just as before. I don't have any fear at all about taking this machine apart. I have saved a small fortune finding the problems myself.