Singer 491D, Service Manual

Page: 14 / 44

Remove and replace the hook shaft in the following manner:-
1. Remove the sewing hook, as instructed on page 8.
2. Mark the two lower bevel gears Z and T, Fig. 17, with chalk or crayon, on
one tooth of one gear and the corresponding space for that tooth in the
other gear. This is important, as these gears may become separated during
removal of shaft. These marks will then make it possible to obtain the
original mating position of the gears.
3. Loosen the two set screws #1 and #2 in hook shaft bevel gear. While holding
the two gears Z and T in mesh, as instructed in Fig. 17, withdraw the old
hook shaft and INSERT THE NEW SHAFT.
4. Replace the sewing hook, as instructed on page 9.
5. Make certain that set screw #1 seats over flat on the hook shaft. Remove
all end shake from hook shaft, pushing gear T, Fig. 17 toward the hook on
the shaft. Securely tighten first set screw #1, then securely tighten the
second screw #2.
6. Time the sewing hook as instructed on page 5.
NOTE: Set screw #1 is the first of the two set screws to appear on the
hub of the bevel gear T as the machine pulley is turned over toward operator.
TO REMOVE AND REPLACE THE HOOK SHAFT
C2
B2
Z
T
#1
#2
HOLD GEARS IN MESH
HOOK SHAFT
- 10 -
Fig. 17