Pfaff 345 User Manual

12. Regulating the Thread Tensions
Regulating the needle thread tension
i"urning tension nut M (Figs. 7 and 13) clockwise increases the tension, turning it counter-
:iockwise decreases it.
t the upper tension is too loose, the bobbin thread draws the needle thread down so
lat it forms small kinks on the underside of the material, as shown in Fig. 8.
: the
upper tension is too tight, the bobbin thread is drawn up to the upper surface of
">e material or the needle thread breaks (Fig. 9).
-oth tensions are correctly balanced if both threads Interlock in the center of the
material, as illustrated in Fig. 10. /
oper tension too loose or lower tension too tight.
jper tension too tight or lower tension too loose.
Fig. 10
ith
tensions correctly balanced.
-len the presser foot is raised, the upper tension is automatically released so tha^
-3 work can be easily removed from the machine. To remove the work, pull it toward
? back (in forward feeding direction), never toward you. as this might cause bending
the needle, skipping of stitches or thread breaking.
egulating tlie bobbin thread tension
<e the bobbin case out of the machine and, using the hook screwdriver, turn screw Z
g. 6) clockwise to increase the tension, or counter-clockwise to decrease It.
e tension is correct if a noticeable resistance of spring Y (Fig. 6) has to be overcome
en pulling the thread out of the bobbin case.
Duckering occurs on delicate fabrics although the tension has been set correctly,
56 both tensions slightly.
13. Regulating the Stitch Length
On all cylinder-bed machines with right-hand balance wheel, the stitch lenght is regu
lated by turning screw S (Fig. 11). Turn this screw clockwise for shorter stitches, or
counter-clockwise for longer stitches. The numbers on the scale indicate the stitch
length in millimeters.
All machines, with the exception of the Pfaff 343 U-12 and 353, are regularly fitted with a
spring-return feed regulator. A tension spring incorporated in this mechanism perma
nently holds the feed regulator lever down in forward feeding position. To backtack
the end of a seam, simply push this iever up as far as it will go. When the lever is
released, forward sewing is resumed instantly.
C'f desired, all machines featuring this type of feed regulator can be equipped with a
;edal which makes it possible to reverse the direction of feed by foot action.
R 7000
:0m
Fig. 11
From the library of: Superior Sewing Machine & Supply LLC

Pfaff 345 Specifications

General

Brand	Pfaff
Model	345
Category	Sewing Machine
Language	English