Brother DH4-B980 instruction manual Adjusting the needle and looper timing

9. STANDARD ADJUSTMENTS

9-2. Adjusting the needle and looper timing

The distance by which the needle bar rises from its lowest position to the position where the tip of the left looper and the center of the needle are aligned should be the same as the distance from its lowest position to the position where the tip of the right looper and the center of the needle are aligned.

Before adjusting the looper timing, first adjust the stitch width (needle racking width).

* Refer to "Adjusting the needle racking width (stitch width)" on page 48. The standard width is 3 mm.

Lowest position	When center of needle
of needle bar	and looper tip are aligned

(1)

(2)

(3)(3)

(4)(5)

0951Q 0952Q 0953Q

1.Move the needle bar to its lowest position.

2.Use calipers to measure the distance between the end of the needle bar (1) and the top of the needle bar bracket (2) when the needle bar is at its lowest position.

3.Turn the upper shaft pulley until the tip of the left looper (4) and the center of the needle (3) are aligned when the needle (3) is at the inside sewing position, and then use the calipers to take the same measurement as taken in step 2. Find the difference between the measurements taken in this step and in step 2.

4.Follow the same procedure as in step 3. above to find the difference between the two measurements when the needle

(3) is at the outside sewing position.

*When the needle (3) is at the inside sewing position, the tip of the left looper (4) should be aligned with the center of the needle (3), and when the needle (3) is at the outside sewing position, the tip of the right looper (5) should be aligned with the center of the needle (3).

*The distance from the end of the needle bar (1) and the top of the needle bar bracket (2) should be the same when the needle (3) is at both the inside sewing position and the outside sewing position.

(9)

(8)

(7)

(6)

0954Q 0955Q

5.If adjustment is necessary, turn the race stand (6) in the direction indicated by the arrow in the illustration, loosen the screw (7), and then move the looper link support (8) up or down to tilt the LS-holder bracket (9) to the left or right (in the direction of the arrow).

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RH-9800