Stitch Length; Differential Feed - Brother CV3440 Operation Manual

Stitch length

The normal stitch length setting is 3 mm. To
change the stitch length, turn the stitch length
adjustment dial on the right side of the machine.
<A>
b
1 Shorten the stitch length to a minimum of 2 mm (5/64 inch).
2 Lengthen the stitch to a maximum of 4 mm (5/32 inch).
<A> Selection mark

Differential feed

There are two sets of feed dogs under the presser
foot to move the fabric through the machine. The
differential feed controls the movement of both the
front and the rear feed dogs. When set at 1, the
feed dogs are moving at the same speed (ratio of 1).
When the differential feed ratio is set at less than
1, the front feed dogs move less than the rear
feed dogs, stretching the fabric as it is sewn. This
is effective on lightweight fabric that may pucker.
When the differential feed ratio is set at greater
than 1, the front feed dogs move more than the
rear feed dogs, gathering the fabric as it is sewn.
This function assists in removing rippling when
sewing stretch fabrics.
„ Differential feed adjustment
Feed ratio Main feed Differential
(rear) feed (front)
Less than
1.0
1.0
Greater
than 1.0
10
a
Effect Application
Material is Prevents thin
pulled tight. materials
from
puckering
Without Normal
differential sewing
feed.
Material is Prevents
gathered stretch
or pushed materials
together. from
stretching or
puckering
The normal setting is 1.0 on the differential feed
adjustment dial.
To adjust the differential feed, turn the dial on the
lower-right side of the machine.
<A>
b
1 Less than 1.0
2 Greater than 1.0
<A> Selection mark
An example
When stretch material is sewn without using the
differential feed, the fabric will be wavy.
To get a smooth finish, adjust the feed ratio from 1.0
toward 2.0.
(The feed ratio required depends on the elasticity
of the material.)
The more elastic the material, the further toward
2.0 the differential feed ratio should be set. Test
sew with a scrap of the fabric to find the correct
adjustment.
CAUTION
When sewing thick non-stretchable material such
as denim, do not use the differential feed as it may
damage the fabric.
a