Brother LH4-B800E Service Manual page 109

4. Adjustment
4-14-4. Adjusting the lower thread clamp opening amount
Approx. 5 mm
1. Loosen the screws q, and then adjust so that the distance between the lower thread clamp t and the lower
thread presser y is approximately 5 mm when the feed guide shaft w is projecting out at the front and is firmly
touching the roller r of opening plate B e.
4 - 22
y
t
e
LH4-B800E
w
r
q