9. STANDARD ADJUSTMENTS
DA-927A, DA-928A
19
9-3. Needle and looper timing adjustment
The correct setting is if the needle height when the looper (1)
moves along its backward travel until its eye is aligned with the
middle of the needle (2) is 0.7 to 1.3 mm (for the 927A) or 0±0.3
mm (for the 928A) lower than when the looper (1) moves along
its forward travel until its eye is aligned with the middle of the
needle (2). If the setting does not match this, adjust by the
following procedure.
1. Remove the presser foot, needle plate and feed dogs. (Refer
to “9-1. Needle bar height adjustment”.)
2. Remove the two screws (3), and then open the belt cover
plate (4).
3. Turn the machine pulley (5) toward yourself until loopers (1)
reach the end of their backward travel.
4. Loosen the bolt (6), and then move the looper holder (7) in
the direction of the arrow so that the distance between the
middle of the needle (2) and the front edge of the looper (1) is
2.1 to 2.3 mm [for the 927A] or 2.7 to 2.9 mm [for the 928A].
After adjusting, tighten the bolt (6).
5. Turn the machine pulley (5) toward you to set the looper (1)
so that its eye is aligned with the middle of the needle (2)
during its forward travel.
6. Loosen the two set screws (9) of the lower belt wheel (8).
7. While holding the looper (1) so that the eye of the looper (1)
does not move from the middle of the needle (2), turn the
machine pulley (5) to raise or lower the needle (2).
If the needle height during the looper forward travel is too
high at this time, turn the machine pulley (5) backward, and if
the height is too low, turn the machine pulley (5) forward.
8. Tighten the two set screws (9) securely.
9. Check that the needle height when the looper (1) moves to
the right from the start of its backward travel until the eye of
the looper (1) is aligned with the middle of the needle (2) is
0.7 to 1.3 mm [for the 927A] or 0±0.3 mm [for the 928A] lower
than the needle height when the looper (1) moves to the left
from the start of its forward travel until its eye is aligned with
the middle of the needle (2).
* If the adjustment is not correct, repeat the adjustment
procedure from step 5 again.
10. Close the belt cover plate (4), and then tighten the two
screws (3).
11. Install the presser foot, needle plate and feed dogs.
4274B
4335B
4275B
<Looper forward travel> <Looper backward travel>
4273B
