Further information is available at ****** This video tutorial for your b48 and b44 provides you with key basic information about the stitch width and the correct knife position. With the dial, you can move the knife position to the left if your seams are not flat enough and there is excess fabric. Alternatively, you can adjust the knife position to the right if your bernette forms loose thread loops while you are sewing. In the video tutorial, we then show you the roll hem lever settings: for overlock stitch, set it to position "N" and for a roll hem, to position "R". The video shows you exactly what the different settings do.