Bernette b68 AIRLOCK - 4-Thread Coverstitch; 3-Thread Coverstitch Wide (LC-RC)

Sewing Test
88
2022-05 EN 50400685.00A.04
Stitch Formation Measures
The seam puckers.
> Reduce RC-Thread tension (yellow).
> Reduce the CL Thread Tension (purple).
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.
4-Thread Coverstitch
Stitch Formation Measures
Needle thread (yellow, green or
blue) forms loops on bottom side of
the fabric.
> Increase the needle thread tension (yellow, green or blue).
> 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, green or blue) too tense.
> Reduce the needle thread tension (yellow, green or blue).
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.
3-Thread Coverstitch Wide (LC-RC)
Stitch Formation Measures
Needle thread (yellow 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
(yellow or blue) too tense.
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.