Originally Posted by
PaperPrincess
Wind two bobbins. Put one on the top and the other in the bobbin. The machine should use thread from top and bottom at about the same rate. You can keep an eye on the one on the top. This is only going to work if you use the same thread in the top & bobbin!
Good idea. I usually notice within a few stitches that the bobbin is empty, but occasionally it goes unnoticed for a few yards.