After using normal stitching I had to go on to 'whip' stitch on the next samples. I've done it the best I can on my sewing machine. It has a bobbin that drops in the top not like my old machine where it went in a case before being put in the machine. That meant I couldn't alter the tension on the bobbin so I had to do the best I could by altering the tension on the top stitch and reducing the pressure on the foot. I also had to stitch from the wrong side so didn't know if it was correct until I'd finished and had a look.
Sample A not a very good example, bit too loose
Sample B getting better
All the following samples have a thicker thread wound on to the bobbin.