SINGER 14T968DC - Manual (Page 90)

Fold T-shirt interlock fabric wrong sides together
lengthwise.
Align the fabric so that the fabric’s fold is not
being trimmed by the knife.
Sew.
Gently pull the fabric flat and press.
Hint:
If the fabric is not laying flat, align
the fabric farther to the left of the
knife.
Three-Thread Flatlock (narrow) page 14