Pfaff 1245 Instruction Manual page 32

Fig. 9 - 02
Place an empty bobbin onto bobbin shaft .
Thread the bobbin in accordance with and wind it clockwise around bobbin
a few times.
Switch on the bobbin winder while at the same time pressing bobbin winder spindle
and lever .
The bobbin fills up while you are sewing.
The tension of the thread on bobbin can be adjusted with knurled screw .
The bobbin winder stops automatically when bobbin is full.
If the thread is wound unevenly:
Loosen nut .
Turn the thread guide accordingly.
Tighten nut .