Singer 14T967DC Workbook page 180

Cover Stitch Narrow
Turn Auto Tension Dial to "K".
Turn Stitch Length Dial to "2.5".
Disengage Upper Knife. The knife will not trim the fabric when it is disengaged.
1. Open Looper Cover.
2. Pull the movable knife holder (silver screw) to the right as far as it will go.
3. Turn the holder counter clockwise until the knife clicks into a lock
position.
Upper Knife Engaged
Cover Stitch Narrow page 3
Upper Knife Disengaged