Chain Yarn; Chapter 3: Stitch Formation; Chain Yarn Feed - Titan DK 2500 Operator's Manual

Chapter 3: Stitch formation

1. Chain yarn feed

It is recommended to keep the pressure on the springs to a minimum on the thread
tensioners A, B and G (FIG 2.1).
Note:
Always make sure the chain yarn is positioned underneath the yarn drawing lever D
(or "take-up") (see FIG. 2.1-3.2). Failure to do so, will result in improper stitch
formation. To avoid this, check if the machine has been threaded properly (see
chapter 2b).
FIG 3.1A: Correct stitch formation, the chain yarn and the needle thread have both
absolutely uniform tensions.
FIG 3.1B: Either insufficient chain yarn tension, or excessive needle thread tension
FIG 3.1C&D: Either excessive chain yarn tension, or insufficient needle thread tension
With the take-up lever D correctly set, the amount of thread thus fed will assure
successful overlocking of the carpet.
In the event of insufficient thread feed (or with thicker carpets), however, undue
tension will be placed on the chain yarn along the edges of the carpets, which in turn
will pull the needle thread from the carpet backing (see figure 3.1C).
To remedy: adjust the take-up lever D slightly in the direction of C3 (see figure 3.5).
Conversely in the event of excessive thread feed (or with thin carpets), the chain yarn
will be found to be slack around the carpet edges (see figure 3.1B).
To remedy: adjust the take-up lever D slightly in the direction of C1 (see figure 3.5).
If the machine isn't equipped with RFR fine adjustment gear (see figure 3.3), the
position of take-up lever D is to be changed as follows:
Untighten the screw of the arm I (figure 3.2) and place the take-up lever D into the
wanted position (higher=less thread, lower=more thread) afterwards, tighten the
screw of arm I again.
RFR fine adjustment assembly: standard in the new machines (from 2004 on)
To adjust the thread feed : loosen the screw J (FIG 3.3). Push the bar (lever)
towards "+" to increase thread feed, towards "-" to decrease thread feed.
Note: For the typical two-thread overlock stitch, insert the chain yarn in the C eye as
illustrated in figure 3.2 and 3.3
For special stitch formation similar to a three-thread stitch (see figure 3.4), pass the
chain yarn through the H eye (see figure 3.2 and 3.3) and then adjust thread feed so
that the stitch thus formed is similar to the one shown in figure 3.4.
From the Library of Superior Sewing Machine & Supply LLC
DK 2500 MANUAL E PAGE 9