Adjusting The Thread Take-Up Amounts Of The Thread Tension Springs - Brother T-8421D Instruction Manual

Adjusting the thread take-up
amounts of the thread tension
springs
The standard thread take-up length for thread take-up
springs R (1) and L (2) is 7 mm. You can adjust the
thread take-up amounts by changing the heights of the
stopper [right] (3) and the stopper [left] (4).
The standard heights of the stopper [right] (3) and
the stopper [left] (4) are when they are aligned with
the center of the tension stud (5). The thread take-
up amount for a thread take-up spring decreases
when the height of the stopper is increased.
<Measurement method>
Adjusting the height of the stopper [right] (3) [for
right thread]
1
Loosen the screw (6), and then slide the thread
take-up spring stopper [right] (3) to adjust its
height.
2
Tighten the screw (6).
Adjusting the height of the stopper [left] (4) [for left
thread]
3
Loosen the screw (7), and then slide the thread
take-up spring stopper [left] (4) to adjust its
height.
4
Tighten the screw (7).
If using a thread trimming sewing machine, the
trailing length for the left upper thread may become
shorter after thread trimming because of the twist
in the thread. The trailing length is normal if the
upper thread length is 35 mm or more when the
thread is pulled from the needle hole. If the thread
length is shorter than this, reduce the thread take-
up amount of the thread take-up spring. However,
if using fine threads (such as #50 polyester thread
or finer), reducing the thread take-up amount too
much may cause the right upper thread to be cut
too short, or it might result in thread trimming
errors for the left upper thread.
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