Singer 132QRFB Mechanical Sewing Machine "lossen tight screws" Questions

screws to the right and slid the metal plate a little closer and the thread is still able to slide around the bobbin case and catch the bobbin thread. But, now when I did a sample sewing, it makes big

...on for me. The screw spoken about is called a set screw, which is a screw that is almost hollow. To lossen or tighten a set screw you use an allen wrench. The one on this machine is 5/64 th size. You ...