Checking The Automa~Ic Mechanism; Regulating The Pressure On The Material - Pfaff 260 Service Manual

Even when stitching delicate fabr ics, the machine must produce a seam which
does not pucker. All of the above tests, naturally, should be repeated with
narrow and wide zigzag stitches. Also try out whether the machine works pro-
perly when you overcast an edge, and check to see that it does not skip stitches
when the needle stitches over the edge.
After switching back to straight stitching, check the performance of the machine
with different needle positions.
Checking the Automatic Mechanism
If the machine in question is equipped with an automatic embroidery mecha-
nism (Pfaff 260-261 and Pfaff 360-261), stitch various embroidery designs to
check the performance of this mechanism. For best results, choose the follow-
ing settings:
D 3- C 2- B left - E 1
D 7- C 3- B left- E 1
D 4 - C 5- B left- E 1
Run the machine slowly and check whether the automatic embroidery mecha-
nism works properly as it gradually changes the stitch width from 0 to 4, and
bock to 0 again. The mechanism must not get stuck in the process, nor should
the thread break.
Before an Automatic is delivered to the customer, it should be oiled thoroughly.
Do not forget to put a few drops of oil on the oil pad which serves to provide
a constant oil film on the rims of the individual pattern cams.
Regulating the Pressure on the Material
The medium amount of pressure for which the presser bar has been set at the
factory will be found adequate for all ordinary sewing operations and need
not be changed. If mostly sheer and delicate fabrics are to be sewn, however,
ease the pressure exerted by the presser bar spring by turning out regulating
screw V (Fig. 75). To increase the pressure for dense and thick materials, turn
screw V inwardly.
Observe these general rules:
Normal pressure:
light pressure:
Strong pressure:
Regulating screw is flush with top of casting.
Regulating screw protrudes about '/s' from top of casting.
Do not turn the screw out too far as, otherwise, it will bear
against the top cover.
Regulating screw is about 3 h6• below top of casting.
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