Installing The Movable And Fixed Knives - Brother b831 Service Manual

Installing the movable and fixed knives
0.05 ~ 0.2 mm
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
Turn the machine pulley by hand until the bobbin case openers are pulled all the way in the arrow direction.
Temporarily fasten the movable knife O with the screws O. and operate the movable knife ©while pressing it with
your finger from above.
(Securely tighten the screws © after theclearance between thetip ofthemovable knife andthe holder bracket issetto
0.05 ~ 0.2 mm.)
Fasten the fixed knife © to the needle plate with the screws ©. (Note the fixed knife has right and wrong sides.)
Fasten the needle plate with the screws © and ©.
Fasten the cover © with the screws ©.
Tilt the head back and install the knife return spring ©.
Return the head to its original position.
Install the needles m the needle clamp and lower the presser foot.
Oil whetstone gg g^jj.g jj^g gjjge is
clean and sharp.
Cutting part
A ragged edge
may result m
thread breakage
If the knives become blunt, sharpen the fixed knives ©
as shown.
The movable knife © cannot be sharpened with an
ordinary whetstone.
If it becomes blunt, replace it with a new one.
Movable knife © torotary hook contact orexcessive knife tohook gap may result in improper thread cutting.
-41 -