I started a quilting project (currently a UFO) right when I got my new sewing machine and I don't recall if I used my old machine or my new machine on the project. After pulling out the project, I see that I have a full bobbin left. A comparison of machine bobbins looks the same but I know one is for a Kenmore and the other for a Brother.
If I accidently use the bobbin for the old machine in my new machine, what will happen?