Suddenly I had NO bobbin tension, retreaded the machine top and bottom, nope, ok, tightened the bobbin screw, nope, read the book, nope, throw the machine out the window nope, clean all the lint out of bobbin case, nope, well, in the bobbin case under the spring hidden from view was a small piece of thread, took forever to pick it out OK! well, nope, tension to tight, fiddle, fiddle ah now it works! What a bunch of malarky! But now it is working great.