Differential Feed; Adjusting The Presser Foot Pressure - Brother ST4031HD Operation Manual

Differential feed

This serger is equipped with 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
slower 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 faster than the rear feed dogs, gathering
the fabric as it is sewn. This function assists in
removing the rippling when serging stretch fabrics.
Differential feed adjustment
Feed Main Differential
ratio feed feed (front)
(rear)
0.7 - 1.0
1.0
1.0 - 2.0
The normal setting is 1.0 on the differential feed
adjustment dial.
To adjust the diffrerential feed, turn the dial on the
right bottom of the body.
<A>
1
2
1 Less than 1.0 2 Greater than 1.0 <A> Selection mark
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
An example
When stretch material is sewn without using the
differential feed, the edge will be wavy.
To get 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.

Adjusting the presser foot pressure

Turn the pressure adjustment screw on the top
left of the machine. You can adjust by referring the
value on the screw.
The normal setting is "2".
1
<A>
1 Less pressure
2 More pressure
<A> Selection mark
2
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