JUKI MO-6000S series Engineer's Manual page 25

Adjustment Procedures
1) Returning amount of the double chain looper
1 Loosen setscrew 2 of double chain lopper driving arm 1 to
make this adjustment.
2 Radius M of the double chain looper driving arm 1 will be
63.4 mm when it is lowered until it comes in contact with stopper
pin 3.
3 For MO-6916G,J type machines, radius M will be 63.2 mm.
4 Adjust the tilt of double chain looper with setscrew 4. Adjust
the tilt to 1.6 mm.
4
2) Longitudinal motion (Avoid motion)
1 Open the cover of the adjusting hole on the rear of the frame,
loosen setscrew 5, and put a ø2 rod in the hole. Now, make
the adjustment by turning the rod back and forth.
Marker : This side
..... Minimum (for standard to thin needle) A
Marker : Far side
..... Maximum (for thick needles) B
3) Clearance between the double chain looper and the needle
1 Temporarily tighten setscrew 2 in the double chain looper,
and finely adjust the longitudinal position of the double chain
looper. Adjust the clearance to 0.05 to 0.1 mm.
MO-6916S,R series only
2 Turn fine adjustment screw 6 clockwise to move the double
chain looper away from the needle.
Turn it counterclockwise to move the double chain looper closer
to it.
Results of Improper Adjustment
™ Excessive return of the double
chain looper will cause frequent
stitch skipping when filament
thread is used.
™ Insufficient return of the double
chain looper will cause frequent
thread stitch skipping when a
spun thread is used.
1.6mm
™ If the avoid motion is too large,
triangle stitch skipping will often
occur.
As observed
from this side
™ Insufficient avoid motion will
cause the needle point to hit the
looper, producing scratches on
the needle point or looper.
™ Excessive clearance will cause
frequent needle thread stitch
skipping.
™ Insufficient clearance will cause
to looper to hit the needle,
leading to needle breakage or
scratches on the looper blade
point with consequent thread
breakage.
21
Bad needle
entry
Good needle
entry