Needle And Rotary Hook Timing - Brother T-8421C Instruction Manual

13. STANDARD ADJUSTMENT

13-7. Needle and rotary hook timing

Needle bar lowest position
Lower feed
69
1. Set the stitch length dial to the actual length of the stitches
2. Remove the rubber cap (1).
3. Loosen the screw (5) and move the needle bar (2) up or
4. Securely tighten the screw (5).
5. At this time, the gaps (A) and (B) between the needle (6)
2203B
6. Turn the machine pulley forward to raise the needle bar
7. In this condition, secure the machine pulley with tape or
The procedure up to this point determines the needle bar lift
amount.
NOTE:
If the needle bar lift amount is too large
• It will cause poor tightening in the right thread.
• Both the left and right seams will become uneven, and
• Upper thread trimming errors may occur, or the upper
• The upper thread trailing length will be too long (models
If the needle bar lift amount is too small
Needle feed
• Skipped stitches and thread breakages will occur.
• The upper thread trailing length will be too short (models
3040M
T-8421C, 8422C, 8452C, 8722C, 8752C
to be sewn.
Standard stitch length
Specifications
-T[]F
-[][]3
-405, -407
down to adjust so that the top reference line (3) on the
needle bar (2) is aligned with the bottom edge of the
needle bar bracket (4) when the needle bar (2) is at its
lowest position.
(Be careful not to turn the needle bar (2) at this time.)
and the front of the feed dog (7) should be about the
same as each other.
(2) until the reference line ((8) or (9), depending on the
feed condition) on the needle bar (2) is aligned with the
bottom edge of the needle bar base (4).
similar, so that the needle bar (2) will not move.
skipped stitches or thread breakages will occur.
thread may be cut too short (models with thread trimmer).
with thread trimmer).
with thread trimmer).
Stitch length dial
2
2
3