Machine Hook Systems.
There are to
basic types of sewing machine hook assemblies. There is
the Rotary Hook assembly. And there is the
Oscillating Hook assembly. Each type has its own features
and benefits. They both do essentially the same
job. It is important to understand sewing machine hook
Sewing Machine Hook Assembly is a
hook that moves in a complete circle. It rotates round and
round. The sewing machine hook slides behind the needle.
It proceeds all the way around the bobbin carrier. It
slides behind the bobbin carrier. Singer sewing machines
revolutionized the sewing world. They
introduced their drop in rotary sewing machine hook
systems. Maintaining the sewing machine hook is a vital
sewing machine repair.
Look at a sewing machine. Look
for where the bobbin is inserted into the sewing machine. There
are basically three locations insert the bobbin. There is
the top loading bobbin. There is the front loading
bobbin. And there are a few models that used a left side
Is the bobbin
a top loading bobbin. Is it placed just below the needle
plate and a slight bit in front of it? If so, it is a
rotary sewing machine hook.
The bobbin may
be inserted in the left end of the sewing machine arm. Or
it may be inserted on the front face of the sewing machine
arm. A bobbin inserted on the left or front may
be a rotary sewing machine hook. Or it may be an oscillating
sewing machine hook.
sewing machine hook moves around in a continuous circular
motion. An oscillating sewing machine hook moves back and
How can you
tell which type of sewing machine
hook assembly you have?
place where you insert your bobbin. Turn the hand wheel
toward you. Watch the sewing machine hook. The
sewing machine hook is a metal piece just outside or behind of
your bobbin carrier. Watch it as it turns. Does it go all
the way around? If so it is a rotary sewing machine hook.
Does it go part way and retrace its path to start over? If so
it is an oscillating sewing machine hook? Knowledge of
the sewing machine hook is essential for sewing machine
Oscillating Sewing Machine Hook Assembly has a sewing machine
hook with a starting position. It begins a few
millimeters to the top left of the needle. It moves to the
right sliding behind the needle. It goes past the needle
and moves around to the bottom of the swing. The oscillating
sewing machine hook travels back again. It moves the same
way to its original position for a return oscillation.
Bernina sewing machines built a superior reputation. It
was based on their advanced oscillating hook system called
a CB Hook.
do essentially the same thing.
The point of
the sewing machine
hook passes behind the needle. It is positioned
slightly higher than the eye of the needle. The upward
travel of the needle causes a small loop of thread to form on
the back side of the needle. This loop is just above the
eye. It is amplified by a space called the scarf. This is cut
out of the back of the needle above the eye. The point of the
hook snags the thread. It moves behind the needle.
It pulls the thread around the bobbin thread. As the needle
rises, the threads are tightened into a lockstitch. Any
variation will require sewing machine repair.
and positioning of the sewing machine hook and needle must
coordinate exactly. Slight variations result in skipped
stitches. It can cause poorly formed stitches. There may
be no stitches at all.
As the hook
and needle travel, they move through a finite pattern. For each
stitch the hook and needle must align perfectly. As the needle
rises, the loop must form on the back of the needle. The point
of the hook must travel to
precisely the right position. It
must arrive at the right moment for the hook to snag
the upper thread. This is called Hook Needle Timing. This
timing is essential for sewing machine repair.
several ways to adjust the hook needle timing. It depends
on the sewing machine model. Some adjust the position of two
interlocking gears immediately below the sewing machine hook.
Some must be adjusted at the right side of the lower shaft.
This is where the lower shaft joins the vertical shaft.
Some must be adjusted by adjusting a timing belt. In all cases,
the needle and hook must meet at the right time in the
right way to form stitches. This is essential for
proper sewing machine repair.
Machine Hook Systems.