Originally Posted by Lady Diana

tell us what model machine you have or is comparable to.....A photo of the "tension disk" you are referring to would be helpful. If your thread is getting under your bobbin and winding around the pin, thread your bobbin in the "Bunny down the rabbit hole" trick. Thread your thread up through the tiny hole on the bobbin, then take the thread down the center of the large hole. Place the bobbin on the spindle and wind your thread. Cut the thread from the spool, then trim off the thread at the little hole location, The reason for a badly wound bobbin is when it is jumping out of the "tension disk" it is loose on the bobbin, then you put the thread back in the disk and the thread winds tighter.....so your bobbin is not wound consistently, thus causing problems with your stitching when sewing. Hope you can figure this out.