Brother T-8421B Instructions Manual page 29

<For all models except foundation
specifications and T-8452B-405>
Do not pass the
thread through.
<For foundation specifications
and T-8452B-405> Center
Pass the thread
through.
(Refer to p.38)
T-8421B, 8422B, 8452B, 8722B, 8752B
4. PREPARATION BEFORE SEWING
If the tension discs are opened as
follows, the thread will become easier
to thread.
<Models with thread trimmer>
Press the tension release plate (2).
<Models without thread trimmer>
Press the tension release plate (2),
or operate the lifting lever or the knee
lifter to raise the presser foot.
The thread can be passed securely
in between the tension discs.
Pass the thread on the inside of the tab (3).
3910M
22