Singer 491D, Service Manual

Page: 23 / 44

11. While maintaining needle bar crank T3 at po-
sition shown in Fig. 39, hold these gears in
mesh by holding the blade of a large screw-
driver between thrust collar and bevel gear
as shown in Fig. 29; then push the end of the
arm shaft V3, Fig. 29 through the bushing W3,
Fig. 29.
12. Using another shaft (or a drift pin of the
same diameter as the arm shaft on these ma-
chines), push the arm shaft V3 further
through the machine (still keeping the gears
at J2 in mesh). This temporary shaft must be
pushed sufficiently Far into the machine to
hold the entire gear and feed eccentric
mechanism in position upon it until the new
arm shaft is installed. When inserting the
temporary shaft (or a drift pin), make
certain that every care is taken to avoid
injury to the oil seal and ring in the arm
shaft bushing (back) and consequent oil
leakage.
13. Finally grasp the needle-bar-crank-end of the
arm shaft firmly at the face plate end and
pull the arm shaft straight out of the
machine.
9. Loosen the two set screws S3, Fig. 28 and remove the machine pulley.
10. Turn the needle bar crank until it is in the position shown at T3, Fig.
30, to prevent crank from disturbing the three wick loops in holder U3,
Fig. 30 during removal of arm shaft.
CAUTION: The feed-timing-bevel-gears at J2, Fig. 29 have been lapped
together at the factory and should be kept in mesh (as instructed in Fig. 29)
throughout the removal and replacement of the arm shaft.
Fig. 30
T3
U3
- 19 -
TIMING MARK
TIMING MARK
HOLD GEARS IN MESH
Fig. 29
J2
V3
W3
Q3