Pfaff 3811-2/45 Instruction Manual page 28

Note: it is useful for the following adjustments to remove the presser foot.
.1 Set the longest stitch length (stitch length adjustment lever 1; fig. 22)
.2 Using the handwheel, bring the needle bar to its t.d.c. (= adjustment hole "1", fig. 21) and lock it in
this position with the cylindrical pin.
.3 Loosen screws 21 (fig. 25) and 22 in the feed lifting cranks.
.4 Loosen screws 23 and 24 in the feeding motion cranks.
.5 Position the main feed dog 6 (fig. 24) and the differential feed dog 7 in the middle of the needle plate
cutout; set the clearance between the feed dogs at 4 mm.
.6 Set the height of the main feed dog at 1.4 mm (move main feed dog carrier 25 either up or
down).
.7 Set the height of the differential feed dog at 1.9 mm (move differential feed dog carrier 26 up or
down).
.8 Position the main feed dog parallel to the needle plate (turn eccentric split ring 27).
.9 Position the differential feed dog parallel to the needle plate (turn eccentric split ring 28).
.10 Taking care to maintain the settings, tighten screws 21; 22; 23; 24.
.11 Remove the cylindrical pin.
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at the maximum stitch length setting and with the needle bar at its t.d.c.
(= adjustment hole "1"; fig. 21):
- the main feed dog 6 (fig. 24) and the differential feed dog 7 should be in the
middle of the needle plate cutout;
- the main feed dog 6 and the differential feed dog 7 should be parallel to the
needle plate (fig. 23);
- the main feed dog should be 1.4 mm above the needle plate;
- the differential feed dog should be 1.9 mm above the needle plate;
- there should be a clearance of 4 mm between the main feed dog 6 and the
differential feed dog 7