Needle And Rotary Hook Timing - Brother S-7780A Instruction Manual

6. STANDARD ADJUSTMENTS

6-7. Needle and rotary hook timing

1787D
57
2291M
0.5 - 0.7mm
1.8mm
3869M
The tip of the rotary hook (3) should be aligned with the
center of the needle (4) when the needle bar (1) moves up
1.8 mm from its lowest position to the position where
reference line (b) is aligned with the lower edge of the needle
bar bush (2) as shown in the illustration.
(The distance from the upper edge of the needle hole to the
rotary hook tip will be 0.5 to 0.7 mm at this time.)
1. Turn the machine pulley to raise the needle bar (1) from
its lowest position until reference line (b) is aligned with
the lower edge of the needle bar bush (2) as shown in the
illustration.
2. Loosen the three set screws (5), and then align the rotary
hook tip (3) with the center of the needle (4).
The distance between the tip of the rotary hook (3) and
the needle (4) should be approximately 0 - 0.05 mm at this
time.
3. Securely tighten the three set screws (5).
S-7780A