SINGER 251 - Manual (Page 12)

See Fig. 15
12
TO WIND THE BOBBIN
Fasten bobbin winder to table with its driving pulley
in front of the machine belt, as shown above, so that
bobbin winder driving pulley will make firm contact
with machine belt when thumb latch is pressed down
and pulley will be released from contact with belt
when sufficient thread has been wound upon the
bobbin.
upon the bobbin. For more thread on bobbin, turn
screw L inward; for less thread on bobbin, turn
screw L outward.
When winding a bobbin with fine thread, a light
tension should be used. Adjust the knurled nut
U, Fig. 15, to regulate the tension.
Place bobbin on spindle, pushing it on as far as it
will go and pass thread through threading points, as
shown above.
If thread winds unevenly on bobbin, loosen screw T
and move tension bracket Z to the left or right, as
required. Tighten screw T.
Wind end of thread around the bobbin a few times.
Press down on thumb latch, pushing driving pulley
over against belt, as shown in Fig. 15. Start machine.
Bobbin winder will stop automatically, when the
amount of thread for which it is regulated is wound
Bobbins can be wound while the machine is
stitching.
NOTE; Occasionally apply a few drops of oil to the
oil well, shown in Fig. 15, on top of the bobbin winder
frame.