5. STANDARD ADJUSTMENT (MACHINE HEAD)
5-4. Shuttle driver needle contact adjustment
5-4-1. First bar tacking
Turn the pulley and align the shuttle hook point with the needle center. Loosen set screw w and turn the eccen-
tric connecting link stud e so that the needle meets the driver q. Note that excessive needle to driver contact
will result in skipped stitches. Also, if the needle does not sufficiently contact the shuttle driver, the shuttle hook
point will interrupt the needle, resulting in abnormal abrasion.
5-4-2. Second bar tacking
NOTE: Check that the needle is protruding from above the needle plate.
1. Turn the drive shaft w w of the lower shaft module q clockwise until the point of the shuttle hook of the
lower shaft module q is almost at the correct timing position.
2. Turn the upper shaft pulley to raise the needle bar from its lowest position until the lowest reference
line on the needle bar is aligned with the bottom edge of the needle bar bracket (needle bar timing
position).
3. Turn the drive shaft w of the lower shaft module q, and then loosen the set screw r and turn the
eccentric connecting link stud t to adjust so that the driver e needle contact touches the needle
when the point of the shuttle hook of the lower shaft module q is aligned with the center of the
needle.
Excessive contact between the needle and the driver e will result in skipped stitches.
NOTE
If the needle does not sufficiently contact the driver,e the point of the shuttle hook will interrupt the
needle, resulting in abnormal abrasion.
Because the upper shaft and lower shaft operate independently of each other, you should check that
the needle does not interfere with the shuttle hook or the driver e when the needle moves inside
the shuttle hook of the lower shaft module.
Also check that the needle does not interfere with the shuttle hook or the driver e in the same way
when the lower shaft module is rotating. Interference can result in broken or bent needles.
q
e
38
e
w
needle plate
r
q
w
t
BAS-705