Pfaff 3811-2/45 Instruction Manual page 22

.1 Set the stitch length at 4 mm (stitch length adjustment lever 1; fig. 7).
.2 Set the control cam 8 (fig. 8) at "0" (turn cam carrier 9 on the shaft).
Note: With the control cam set at "0", the actuating lever 10 must have a little bit of play;
see arrow in fig. 8.
.3 Loosen clamp screw 11 (fig. 9) just enough so that the reversing crank 12 can only be turned on its
shaft using much force.
.4 While continuing to turn the handwheel, change the position of the reversing crank 12 (fig. 10)
so that the main feed dog 6 (fig. 6) and the differential feed dog 7 carry out the same motion.
.5 Tighten clamp screw 12 (fig. 10).
22
at:
- stitch length 4 mm
- cam setting "0"
both bottom feed dogs (main feed dog 6 and differential feed dog 7; fig. 6)
must make the same movement when the handwheel is turned.