Bernette Airlock b64 - 3-Thread Narrow Seam

Sewing test
64
2020-09 EN 5040064.00A.04
3-Thread Narrow Seam
With a balanced stitch formation, the looper thread (blue/red) are intertwined at the fabric edge.
The needle thread (green) is identifiable on the top side of the stitch as a straight line and on the bottom side
of the stitch as points.
Stitch pattern Recommendation
The looper threads are intertwined on the
wrong side of the fabric.
> Reduce the lower looper thread tension (red).
> Increase the upper looper thread tension (blue).
The looper threads are intertwined on the
right side of the fabric.
> Reduce the upper thread tension (blue).
> Increase the lower looper thread tension (red).
The right needle thread forms loop on the
wrong side of the fabric.
> Increase the right needle thread tension
(green).
The fabric edge doesn't curl as intended.
> Increase the upper looper thread tension (blue).
> Increase the lower looper thread tension (red).
> Increase the cutting width «CW».
> Shorten the stitch length «SL».
> Check the rollhem selector lever position «R».
Tab.2: Optimizing the stitch: 3-Thread Narrow Seam