Adjusting The Needle And Rotary Hook Timing - Brother S-7220B Instruction Manual

13. STANDARD ADJUSTMENTS

13-10. Adjusting the needle and rotary hook timing

0 - 0.05 mm
<Presser foot
including
finger guard>
<Seen from above>
<-4[]3> 0.4 - 0.7 mm
<-405> 0.6 - 1.1 mm
55
0.5 - 0.7 mm
<-4[]3> 1.8 mm
<-405> 2.2 mm
3775M
0 - 0.05 mm
3776M
3777M
3778M
When the machine pulley is turned forward to raise the
needle bar (1) 1.8 mm (2.2 mm for -405 specifications) from
its lowest position, the rotary hook tip (3) should be aligned
with the center of the needle (4) as shown in the illustration
when the distance from needle plate mounting surface A to
the bottom edge of the needle bar (1) is the same as the
height of surface C on the <2> side of the accessory timing
gauge (2).
(At this time, the gap between the upper edge of the needle
hole and the rotary hook tip (3) will be 0.5 - 0.7 mm.)
1. Remove the presser foot (5), needle plate (6) and feed
dog (7).
2. Set the stitch length dial as follows.
<-4[]3>... Stitch length dial 0 setting.
<-405>... Stitch length dial 3 setting.
3. Loosen two of the three set screws (9) which are securing
the rotary hook (8).
4. Turn the machine pulley to raise the needle bar (1) from
its lowest position until the distance from needle plate
mounting surface A to the bottom edge of the needle bar
(1) is the same as the height of surface C on the <2> side
of the accessory timing gauge (2).
5. Loosen the remaining set screw (9) and align the rotary
hook tip (3) with the center of the needle (4). There should
be a gap of 0 - 0.5 mm between the rotary hook tip (3)
and the needle (4) at this time.
6. Securely tighten the three set screws (9).
7. Install the feed dog (7), needle plate (6) and presser foot
(5).
<Checking the clearance between the rotary hook and
bobbin case holder position bracket>
Check that the clearance between the rotary hook (8) and the
bobbin case holder position bracket (10) is enough to allow
the thread being used to pass through smoothly.
The clearance should be 0.4 - 0.7 mm for -4[]3 models, and
0.6 - 1.1 mm for -405 models.
S-7220B