Singer 14T967DC Workbook page 151

10. Thread the looper eye (A) from front to back. Pull about 4 inches of thread.
Position thread into V cutout (B) on threader. Firmly hold thread tail with left
hand and pull Threader lever (C) up into place (D).
"V" cutout
NOTE: Make sure the Upper Looper thread is
behind the Lower Looper thread.
Five-Thread Safety Stitch Wide page 10
Threader Lever