T-8421C, 8422C, 8452C, 8722C, 8752C
13. STANDARD ADJUSTMENT
71
<For T-8452C and T-8752C>
13. Use an oil-based marker pen to color in the hollow of the
needle.
14. With the needle raised, turn the machine pulley forward
while pushing the needle against the rotary hook tip (15)
with your finger to make a mark from the rotary hook tip
(15) in the hollow of the needle.
15. Check that the distance (C) from the intersection
between the mark from the totary hook tip (15) and the
center line of the needle to the top edge of the needle
hole is 1-1.5 mm.
If using a thread such as polyester thread which does
not easily form stable loops
* If problems such as skipped stitches or upper thread
breakages occur, set the above distance (C) to 0.7–0.8
mm to make it easier for the rotary hook tip (15) to catch
the upper thread loop.
NOTE:
• When the stitch length is changed, distance (C) will also
change, so re-check distance (C) at such times.
• During quick reverse operation, distance (C) for the left
needle will become shorter, so do not set it to less than
0.7 mm, otherwise the rotary hook tip (15) may touch the
projection (D) and this could damage the rotary hook tip
(15).
16. Loosen the set screw (16) and then pull the needle bar
clamp (17) downward to remove it.
17. Turn the screw (18) to adjust so that the distance from
the upper edge of the needle hole to the rotary hook tip
(15) is 1-1.5 mm.
18. After adjustment is completed, insert the needle bar
clamp (17) into the hole of the needle bar (2) as far as it
will go, and check that the distance is 1-1.5mm. Secure
it by tightening the set screw (16).
13-8. Installing the feed dog
1. Install the feed dog (1) to the feed bar (2) with the two
screws (3).
2. Tighten the feed dog support set screw (4) so that the tip
of the set screw (4) touches the bottom of the feed dog
(1).
3. Tighten the nut (5) to secure the set screw (4).
* The set screw (4) is not used for installing the feed dog at
an angle.
3060M
Touch
3043M
Color in
Mark
3185M
Mark
Lower
Higher
Insert the needle clamp all the
way into the needle bar.
2205B
Needle center
Lowest position