SINGER 1525 - Manual (Page 53)

Turn stitch length dial to "1" -"4", the stitch width can be
adjusted to suit the fabric.
The overedge stitches are suitable for finishing seams and
preventing them from fraying.
When finishing, the needle should just go over the edge of the
fabric.
Use new needles or ball point needles or stretch needle!
Attention:
Overedge stitches GB
0
1 2
3
4
5 0
1 2 3
4
5 0
1 2 3
4
L
1
46