Pfaff 3334 User Manual

The main tension remains inactive during the first four stitches of the tack
in order to prevent the fabric from being contracted while the first long
stitches are being sewn. {This applies only to bartacks made with exception
ally long starting stitches and on very thin fabric). The main tension remains
inactive also during the last stitches of the needle cycle so that an adequate
amount of thread can be pulled through the tension for the trimming ac
tion.
(3) Bobbin Thread Tension
Set the bobbin thread tension so that the bobbin thread will be pulled into
the fabric correctly. Moke sure, however, that the tension is not too light as
otherwise the bobbin thread will not be cut.
Correct Tension Regulation
Fig. 45
The neot oppeorance of the finished seam and its durability greoHy depend on the correct
regulation of tensions. The tensions ore correctly balanced if the needle and bobbin threads
interlock in the center of the material, os iliustroied.
This seam looks ugly and is not durable.
The bobbin thread pulls the needle thread to
the
underside of the fabric as the stitch is
being formed.
Goose: Needle thread tension too weak, or
bobbin thread tension too tight.
Remedy; Increase needle thread tension or
decrease bobbin thread tension.
This seam looks ugly and is not duroble,
The needle thread pulls the bobbin thread to
the surface of the fabric as the stitch is being
formed.
Cause: Needle thread tension too tight, or
bobbin thread tension too weak.
Remedy: Decrease needle thread tension or
increase bobbin thread tension.
(4) Lifting Lever
After the machine hos stopped, the left treadle is depressed to pull down
the lifting lever and raise the clamp feet. At the same time, the knife bar
is actuated and causes the knives to swing forward from the stand-by to the
cutting position. This action causes the needle thread loop to be pulled
over the cutting edge of the needle thread knife and be trimmed. Simultan
eously, the bobbin thread which passes in front of the cutting edge of the
bobbing thread knife is pulled tout and cut.
To adjust the throw of the knives, loosen screw C (Fig. 34) and move the
bracket on the lifting lever forward or backward. The setting Is correct
if the tip of the bobbin thread knife is flush with the edge of the needle
plate when the lifting lever has been depressed completely.
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From the library of: Superior Sewing Machine & Supply LLC

Pfaff 3334 Specifications

General

Brand	Pfaff
Model	3334
Category	Sewing Machine
Language	English