Remove the top cover and tilt back the machine head.
Turn the machine pulley by hand so that the index mark (1) is near facing straight upward.
Loosen the bolt (2).
Use the spanner 10 to turn the nut (3) counterclockwise until it stops.
In this condition, move thread trimmer rod H (5) forward or back to adjust so that the distance between the ridge line on the right side of the needle plate and the ridge line on the movable knife (4) is 9 mm.
Tighten the bolt (2), and then check the above position once more.
Loosen the nut (6), and then turn the set screw (8) to adjust so that the outside of the hole in the movable knife (4) is aligned with the ridge line on the shuttle race thread guide (7).
Tighten the nut (6).
Turn the pulley by hand to set the needle bar to its lowest point.
Check that the collar (9) is not touching the inside of the thread trimmer cam (10). Furthermore, push the driving lever (11) by hand toward the thread trimmer cam (10) so that the collar (9) goes into the groove of the cam, and then release your hand and check that the driving lever (11) returns smoothly to its original position.