Singer 7258Q - Stitch Length

Page 26/37
Original issue
January 2009
Service Manual
COSMO-7/8
series
Model
15. Stitch length
(A) Checking meshing position of gears
This procedure is needed only when disassembling and re-assembling cams.
Rotate motor gear clockwise to touch it with stopper pin and mesh these gears so that
feed regulator gear may be positioned with full two gears below line from feed regulator to
motor gear
(B) Origin point positioning of stitch length
Step motor rotates 7.5 degrees with one pulse and ratio of motor gear vs. feed regulator
gear is 1:5. This amount of rotation makes feed regulator rotate 1.5 degree. This amount
of rotation makes stitch length vary by 0.25 mm. 0.25 mm stitch pitch moves at each of 7.5
degree exciting position.
Full two gears below line
Stopper pin
Projection (1)
Switch is
turned on.
Stopper pin
Switch