When I first bought the first Viking (+1 or 1+) in 1999, I was told not to wind polyester thread fast because it would tighten the plastic bobbin up on the spindle, and it is not easy to remove it unless the thread is unwound first. I forgot one day, and it was a pain to unwind the thread. It is rather annoying the bobbins were specially made for this model and generic metal bobbins could not be used, instead. When I buy my next machine, it will take metal bobbins as well as plastic ones.