My thread was doing that extra threads bit, when my bobbin case wasn't put in properly. My bobbin is a top load, but the case wasn't snapped into place all the way, therefore the bobbin itself wasn't rolling properly and the top thread was catching on part of the bobbin case mechanism. It created quite a mess.
I don't know if that would cause a problem in the side load bobbins.
Edited to add: The bobbin case was only off about 1/100ths of an inch. I had a hard time figuring out the problem.
Last edited by Barb in Louisiana; 01-13-2015 at 08:39 PM.