Singer 491D, Service Manual

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3. Turn machine pulley as required to reach screw T2, Fig. 22, in needle bar
crank through hole left by removal of plug S2, Loosen set screw T2.
4. Using wrench 545945 (through same hole) and turning machine pulley as re-
quired, loosen the large hexagon head clamping screw U2, Fig. 22 on needle
bar crank.
CAUTION: DO NOT DISTURB the smaller hexagon head position screw V2, Fig.
22 which holds the needle bar crank at its correct position on the horizontal
arm shaft.
5. Loosen small set screw W2, Fig. 21 in the rear of the arm of the machine.
6. Insert a face plate screw X2, Fig. 21 in the tapped hole in center of stud
Y2, Fig. 21 and, while holding back the needle thread take-up link inside
the head at 22, Fig. 21, pull upon the screw X2 until the stud Y2 is re-
moved. Remove face plate screw from stud.
7. Back the end of the take-up A3, Fig. 21 toward the inside of the machine,
turning the machine pulley as required until the take-up is free of the
slot provided for it.
8. The needle thread take-up link assembly (including parts B3, Z2, A3, C3,
D3 and E3) can now be pulled free of the needle bar crank.
To replace the needle thread take-up:-
1. Make sure that the wearing plate C3 is in place and undamaged on the face
of the needle bar crank, as shown in Fig. 21.
2. Place the needle thread take-up link 22 and take-up A3 in the head of the
machine so that the stud E3, Fig. 21 in the center of the linkage slips
into the hole provided for it in the needle bar crank, as shown in Fig. 21.
3. Slip the upper end of the take-up A3 through the slot provided for it in
the head of the machine.
4. Insert stud Y2 through needle thread take-up lever link z2 and into its
hole in the machine casting so that the oil wick fitted to the stud Y2
faces upward. DO NOT INSERT THE STUD TO ITS FULL DEPTH AT THIS TIME. There
should be about .25 to .38 mm side play of the take-up lever link
Z2 on the stud, until final adjustment is made in Step 15.
5. Turn the set screw W2 inward lightly against the flat on the stud Y2. DO
NOT TIGHTEN screw W2 until final adjustment is made in Step 15.
6. Turn machine pulley as required to make set screw T2 in needle bar crank
accessible through hole at S2, Fig. 22 in rear of machine head.
7. Insert a screwdriver through this hole and, while turning stud E3 by hand
to find its flat, turn set screw T2 until it bears tightly upon the flat.
8. Turn screw T2 back, just enough to "break it loose".
9. Test for side play by pushing take-up lever A3 gently right and left;
there should be .025 to .05 mm side shake between lever and wearing plate.
10. Move thread take-up crank inward or outward in needle bar crank, as re-
quired, to obtain clearance.