Adjustments - UnionSpecial 4500A Original Instruction Manual

ADJUSTMENTS

CAUTION: When adjusting the machine or replacing parts, always disconnect the Electric Cord
from the power source. This is crutial for the safety of the operator and the adjuster.
2.5-3.5mm
1. Thread Tension (Fig. 10)
The thread tension spring is preset at the factory to sew
PP woven cloth bags. If adjustment is required, first loos-
en screw (A) No. 450106 and adjust the thread tension
nut (B) No. 450105 as per Fig. 10. When the adjustment
is finished, retighten screw to lock the thread tension nut.
If this is not done, the stitch will not remain uniform.
2. Position of Needle and Looper (Fig. 11)
Looper must pass the concave part of Needle with
clearance of 0.1 mm as shown in Fig. 11. Adjustment of
the clearance can be done after loosening the screw of
Looper Rocker.
3. Position of Feed Dog (Fig. 12)
When installing a new feed dog ensure that it is posi-
tioned correctly onto the feed dog carrier block and light-
ly tighten the fixing screw. Check that the feed dog teeth
are 2.5-3.5 mm above the throat plate when the feed
dog is in the top dead center before finally tightening the
fixing screw.
4. Pressure of Presser Foot
When adjusting the presser foot pressure, take out
the Needle Bar Guard and loosen Screw of Presser
Bar Connection. Raise the Presser Bar to increase the
pressure and lower to decrease the pressure. After the
adjustment, tighten the Screw firmly.
5. Presser Foot Lifter
The Presser Foot Lifter is used to lift the Presser Foot
and pull out the bag from under the Presser Foot in case
of a problem such as bag or thread jamming.
6. How to use the Hook
The Hook on the Pulley Cover is used to install a Shoul-
der Belt or a Hanger.
11