Rough Adjustment Of Zigzag Stitch; Fine Adjustment Of Zigzag Stitch; Zeroing The Needle For Straight Stitching - Pfaff 260 Service Manual

c. the lobe of eccentric stud A in the needle bar frame (Fig. 107) points up-
word, and
d. the
clearance at f (Fig. 104) is
5
/32", or 4 mm.
Important
The needle of a z igzag sewing machine must not make any sideways motion
when it is down in the goods.
Rough Adjustment of Zigzag Stitch
Turn the needle bar crank until its lobe points upward. Rotate the needle
vibrating eccentric bevel gear and the feed eccentric so that their timing marks
are at the top. Now mesh both bevel gears so tha t they rotate smoothly with-
out having any play.
Fine Adjustment of Zigzag Stitch
With the machine set for the widest stitch width, the descending needle should
cease vibrating when its point has reached o position about
sla2"
to
1 /•",
or 4
to 6 mm, above the needle plate.
If flne adjustment is required, turn the bevel gear on the arm shaft, as appro-
priate (see also the second paragraph on page 48).
As you make this adjustment, take core that you do not disturb the correct
meshing of the bevel gears and that you preserve the correct amount of ploy.
Zeroing the Needle for Straight Stitching
While at the factory this adjustment is performed with the aid of a dial gauge,
our service personnel in the fleld should best follow the procedure outlined
below:
a.
Using Finger-Tip Control F
Insert a new No. 80 needle, attach the buttonhole foot, and drop the feed
dog. Place a p iece of white cardboard between the needle plate and the
sewing foot. Now
turn stitch width dial A to "4",
set needle position lever Bat its central position, and
push finger-tip control F up.
Turn the balance wheel forward, then backward, and let the needle stitch
into the cardboard lightly. The needle is zeroed correctly if it st. i tches into
the same spot twice, without being deflected.
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