Brother HE-800A User Manual
Page 84
HE-800A
10. STANDARD ADJUSTMENTS
76
ውዌ-ዓ-ዎ. Adjusting the upper thread scissors opening timing
After setting the sewing machine to the home position, press the RESET key and then make the adjustment.
Gradual opening timing adjustment
1. Loosen the two bolts (3), and then adjust so that the distance (b) between ridge line (B) on the opening cam (1) and
the upper thread scissors (2) is 0.5 mm, and so that ridge line (B) on the opening cam is parallel to the feed
direction.
2. Loosen the two screws (4), and then adjust so that the distance (c) between the rising section (C) of the upper
thread scissors (2) and the tip of the opening cam (1) is approximately 0.5 mm when the upper thread scissors (2)
are closed.
* If you would like the scissors to start opening earlier, make the distance smaller. However, if you make the
distance smaller, check that the rising section (C) of the upper thread scissors (2) does not touch the opening cam
(1) and prevent the upper thread scissors (2) from opening when the work clamp is lowered.
3. Apply grease to the inclined face (D) of the opening cam (1).
Scissors fully opening timing adjustment
1. Loosen the two bolts (7), and then adjust the support plate (8) so that the back plate (5) and the cam (6) overlap by
approximately 1.0 – 1.5 mm.
Note: If the amount of overlap is too small, the upper thread scissors will not open properly and the upper thread
scissors and the cutter may touch each other.
2. Loosen the two bolts (9), and then adjust the clearance between the bend in the back plate (5) and the cam (6) to
approximately 2 mm.
* If you would like the scissors to start opening earlier, make this clearance smaller.
3. Check that the upper thread scissors (2) open smoothly during feeding.
Note: If the upper thread scissors (2) do not open smoothly, the upper thread scissors (2) may touch the cutter and
needle breakage may occur.
4106M
3987Q
Approx. 2 mm
Approx.
1.0 – 1.5 mm
4105M
Start touching at 1.5 – 2.5 mm
Feed arm
Approx. 0.5 mm
4104M
Start touching
at 1.5 - 2.5 mm
Approx. 0.5 mm