SINGER 14T967DC-WORKBOOK QUANTUMLOCK - Manual (Page 87)

Three-Thread Flatlock (narrow) page 11
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).
NOTE: Make sure the Upper Looper thread is
behind the Lower Looper thread.
Threader Lever
“V” cutout