The 15k80 was clean and lubed so the time had come to see how it sews.
I mentioned yesterday that I am new to the 15 class but with the help of various down loads I have now educated myself as to how these machines should be threaded top and bottom.
Three bobbins came with the machine. I used my smallest screwdriver to adjust the sloppy bobbin case.
I had disturbed the top tension earlier because I had taken the tension unit apart to check the face of the tension discs for lint, dirt and rust before threading and somehow the tension on the bobbin case seemed a bit "free" to me. With these things in mind I was not expecting great stitches from this machine.
In my first attempt the top tension was too great and the bottom tension too little. Result: little bumps of bobbin thread on the top of the goods and a wonky line of stitches. I wasn't keen to muck about with the bobbin case at this stage so I backed off the tension for a few turns until the bumps nearly vanished. I got to the stage where I couldn't feasibly back the top tension off any further so threw caution to the wind and tightened the screw on bobbin case a quarter turn. A little more playing and these are the most recent results.
This is a piece of old shirt cuff left over from a quilting project. So the machine is sewing through two layers of fine cotton and a layer of interfacing. It may not be very easy to see but the stitches (approx 15 per 1 inch) are locking in the middle of the fabric sandwich and the row feels smooth to the touch on both sides. By George I think we've got it!