Abstract: In a rotary hook, lockstitch, stationary bobbin case sewing machine, a bobbin is mounted on a bobbin ejector carried on the center post of an open ended bobbin case. A thread tensioner is attached to the outside of the bobbin case. Illumination is provided and the thread supply can be viewed at any time through a magnifying window and the exposed flange of the bobbin. Release of a latch on the center post permits removal and replacement of the bobbin without detaching any other part.