Bernette b68 AIRLOCK - 3-Thread Coverstitch Narrow (LC-CC); 3-Thread Coverstitch Narrow (CC-RC); 3-Thread Picotstitch

Sewing Test
89
2022-05 EN 50400685.00A.04
3-Thread Coverstitch Narrow (LC-CC)
Stitch Formation Measures
Needle thread (yellow or green)
forms loops on bottom side of the
fabric.
> Reduce the CL Thread Tension (purple).
> Increase the stitch length SL.
> Check threading path.
Chain looper (purple) thread loose
on the bottom side of fabric.
> Increase the CL Thread Tension (purple).
> Increase the stitch length SL.
> Check threading path.
Chain looper (purple) thread too
tense, seam is tunneling.
> Reduce the CL Thread Tension (purple).
> Reduce the stitch length SL.
> Check threading path.
The seam puckers. Needle thread
(yellow or green) too tense.
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.
3-Thread Coverstitch Narrow (CC-RC)
Stitch Formation Measures
Needle thread (green or blue) forms
loops on bottom side of the fabric.
> Reduce the CL Thread Tension (purple).
> Increase the stitch length SL.
> Check threading path.
Chain looper (purple) thread loose
on the bottom side of fabric.
> Increase the CL Thread Tension (purple).
> Increase the stitch length SL.
> Check threading path.
Chain looper (purple) thread too
tense, seam is tunneling.
> Reduce the CL Thread Tension (purple).
> Reduce the stitch length SL.
> Check threading path.
The seam puckers. Needle thread
(green or blue) too tense.
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.
3-Thread Picotstitch
Stitch Formation Measures
Upper looper thread (blue) wraps
fabric edge too loosely.
> Increase UL-thread tension (blue).
> Increase the cutting width CW.
> Reduce the stitch length SL.
The fabric edge doesn't curl as
intended.
> Increase the cutting width CW.
> Increase UL-thread tension (blue).
> Reduce the stitch length SL.
> Check the rolled hem selection N/R position.