4. ADJUSTMENT
HE-800A
97
4-15-3. Adjusting the lower thread clamp opening timing
1. Loosen the set screw (2) of the feed arm support (1), and then align reference line A of feed guide shaft B (3)
with the edge of the feed arm support (1).
2. When the feed mechanism moves by 6 - 7 mm, the opening plate (4) moves and the lower thread clamp (5)
opens.
3. To change the opening timing, loosen the set screw (2) and move the feed guide shaft B (3) to the left or right to
adjust.
* The end of the thread which is being held by the lower thread clamp (5) is wound around inside the seam. If the
opening timing is too early, it can cause problems such as poor winding or pulling-up of the lower thread. If the
opening timing is too late, it can cause problems such as stretching, uneven seams or bird’s nests at the sewing
start, depending on the type of material.
Note:
After moving the lower thread trimmer cam lever (6) back in the direction of the arrow, move the feed
mechanism.
If the feed mechanism is moved when the lower thread trimming has been carried out, the mechanisms will
press against each other, which may result in damage to the lower thread clamp (5) and the opening plate
(4).
4349Q
4348Q
4347Q
4346Q
Approx.
6 - 7mm
Sewing start
Lower thread winds around seam
Lower thread releases from
lower thread clamp
