- 23 -
upper looper thread
needle thread
lower looper thread
3-thread chain stitch (overlock)
Figure 59 shows you the stitch pattern for this stitch.
This stitch with a needle and 3 threads is used for tidying of normal fabrics
with an overcast stitch.
By changing the needle position you can obtain a narrow or a wide overcast
seam.
Adjust the thread tension selectors
r t z u
to the appropriate values
(see table) then sew a test seam on the material being used.
Should the upper looper yarn lie on the underside of the textile (Fig. 60):
• turn the thread tension selector
z
for the upper looper thread (red) to a
higher number, or ...
• turn the thread tension selector for the lower looper thread
u
(yellow)
to a lower number.
Should the lower looper yarn lie on the upperside of the textile (Fig. 61):
• turn the thread tension selector for the lower looper thread
u
(yellow)
to a higher number, or ...
• turn the thread tension selector
z
for the upper looper thread (red) to a
lower number.
Should the needle thread appear to be too loose (Fig. 62), turn the thread
tension selector for the needle thread (blue
r
or green
t
) to a higher
number.
Textiles
Tensioning the thread
blue
green
red
yellow
light
material
2.0
-
2.0
1.0
medium-
weight
material
3.0
-
2.0
1.5
heavy
material
3.0
-
3.0
1.5
Textiles
Tensioning the thread
blue
green
red
yellow
light
material
-
2.0
7.0
2.0
medium-
weight
material
-
2.5
6.5
2.5
heavy
material
-
3.5
6.5
2.5
Needle position
Seam width switch
S
Stitch length
2 - 4
Upper looper element
not necessary
Top
Underside
Correct thread tension
Incorrect thread tensions
Top
Underside
needle thread
lower looper thread
upper looper thread
Top
Underside
needle thread
lower looper thread
upper looper thread
Top
Underside
needle thread
lower looper thread
upper looper thread
Fig. 59
Fig. 60
Fig. 61
Fig. 62
