Ok - call me uneducated. I read the other referenced thread as well. I know about (and do) holding the tails of thread when piecing...typically don't use leaders/enders because my machine doesn't care. But how do you you get the bobbin thread to the top of your work in the middle of a quilt??? Not really an issue for me personally as I hand quilt, but just very curious as to the mechanics of the process.