Figure 9-49.Timing sewing hook.
position, the point of the sewing hook should be
at the center of the needle (fig. 9-49).
If the sewing hook is not timed correctly,
loosen the three setscrews in its hub. Turn the
hook on its shaft to align the point with the center
of the needle, as shown in figure 9-50. Tighten
the three setscrews.
To Remove and Replace
the Sewing Hook
Remove the needle, slide plate, and bobbin
case. Take out screw (D of fig. 9-50) and remove
hook retainer (E of fig. 9-50). Loosen the three
setscrews in the hub. Turn the handwheel until
the thread guard (widest part) of the hook is at
Figure 9-50.Sewing hook.
Figure 9-51.Removing sewing hook.
the bottom, then remove the sewing hook from
its shaft (fig. 9-5 1).
When installing a new sewing hook, have the
thread guard at the bottom. Now turn the bobbin
case holder until the notch (F) is at the top.
Replace the hook retainer (E) watching that the
projection (G) near its end (fig. 9-50) enters notch
(F) in the bobbin case holder. Fasten the hook
retainer to the underside of the bed by means of
its screw. Replace the needle and time the sewing
hook as described in the preceding paragraph.
Reinstall the bobbin case, throat plate, and slide
Timing the Feeding Mechanism
The feeding mechanism is timed at the factory
for average stitching performance. Normal timing
is such that the feed dog teeth, rising from their
lowest position, should be just flush with the
surface of the throat (needle) plate after the needle
point has traveled about 5/16 inch above the plate
while on its upstroke.
To adjust the feeding mechanism, remove the
top cover from the machine. Turn the handwheel
toward you until the two setscrews, which lock
the feed eccentric into the main shaft, come into
view (fig. 9-5 1). Loosen both setscrews; lightly tap
the feed eccentric toward you to advance the feed
timing. To retard the feed timing, tap the eccentric
to rotate it toward the rear of the machine.
The FAA is working with its aviation security partners in...