Specifications

Checking the under thread presser is done in two parts. First by looking at the part
itself to see if there has been any "crumpling" as shown in the bottom left section
of Figure 4-9.
Crumpling is damage caused by the movable knife hitting the under thread presser.
If you see visual evidence of any damage, replace the under thread presser as
described earlier in this chapter.
The second part of checking under thread presser is to check if the bobbin thread is
in fact being held in place.
1. While the machine is still turned off, remove the font bed cover and disconnect
the connecting link from the movable knife drive arm by lifting it from the front
pin (see Figure 4-7).
2. Pull the movable knife forward with a small hex wrench hooked behind it.
3. Leaving the bobbin case in the rotary hook, pull off some bobbin thread, and
drape it over the movable knife as shown in Figure 4-10.
4. With the bobbin thread draped over the movable knife from back to front, gently
hold the thread so there is some slack and then push the movable knife back
until the thread is cut. This cut should be clean, and should not be frayed.
If the thread is frayed you may need to replace the adjustable fixed knife, adjust the
adjustable fixed knife, replace the movable knife, or any combination of these items.
5. The "top" thread should be loose and fall away, because it has no support. The
"bottom" thread should be held in place under the movable knife by the under
thread presser.
1. Drape some Bobbin Thread
over the Movable Knife
from front to back.
2. Push Movable Knife
back with your thumb or
forefinger to cut the thread.
Figure 4 - 10 Checking The Cut
Under Thread Presser 4 - 15
110291-01, Rev D 4. Trimmer Maintenance