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RELATIONSHIP BETWEEN NEEDLE AND HOOK
The relationship between the needle and the hook is called timing. Timing between the needle and the hook
is correct when the main shaft is 200 degrees.
THE ROTATING HOOK ASSEMBLY
The hook assembly, located beneath the throat plate, is the home of the bobbin case and bobbin. The inside
of the hook assembly is called the basket, and is surrounded by the assembly raceway. The basket cradles the
bobbin in the case after it has been placed on the shaft of the hook assembly.
The hook assembly has a hook point that is used by the sewing head to lock the top thread to the bobbin
thread to form the stitch. As the machine is sewing, the bobbin in the case and the needle moves with the
point of the hook. The timing of the passage of the hook point and the point of the needle is extremely
important. If the hook approaches the loop too early, the hook point will not intercept the loop. The loop will
be formed after the hook point has passed the needle, which will result in skipped stitches, and broken
thread. If the hook approaches the loop too late, the loop will not be available when the hook point reaches
the needle. Again, skipped stitches and broken thread will be the result.
Gap of Hook
TIP
It is a good idea to use a Size 11 needle when adjusting the timing. Although
needle size increases toward the front – the scarf and the back dimension
remaining the same – it is just good insurance to use this popular size, and use it
each for each timing procedure.
CAUTION
The hook can move from the right to the left
according to the allowance of the lower shaft gear.
When the timing is correct, there is no movement
when turning the hook clockwise.
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