Whether you enjoy repairing sewing machines as a hobby, a job, or your own business, it can be both exciting and challenging. There are so many different models and designs, it can be difficult to keep up.
At first, fixing sewing machines can be an overwhelming task. There are so many different makes, models, and designs to learn. When you look at sewing machines, they may all look alike. As soon as you start taking off the covers, you discover just how different they really are. The hook assembly is one of the things that every sewing machine user should and every technician must understand.
When you look at a sewing machine, one of the first things you need to identify is if the machine has an oscillating or a rotary hook assembly. They do much the same task on your sewing machine, but they do it very differently.
The Rotary Hook Assembly includes a hook that moves in a complete circle round and round. The hook slides behind the needle, and proceeds all the way around the bobbin carrier until it again slides behind the bobbin carrier. Singer sewing machines revolutionized the sewing world with their drop in rotary hook systems.
Where do you put the bobbin on this machine? I could be inserted in front, or top under the needle plate, or on the left end of the machine. If it is a top loading bobbin, the machine is usually a rotary hook machine.
If the bobbin is inserted in the left end of the sewing machine arm or on the front face of the sewing machine arm, it may be either a rotary or oscillating hook.
A rotary hook moves around in a continuous circular motion. An oscillating hook moves back and forth. How can you tell which type of sewing machine hook assembly you have?
To double check you thinking, does the point of the hook go all the way around the carrier (Rotary Hook) or only part way (Oscillating Hook)?
The Oscillating Hook Assembly involves a hook that begins a few millimeters to the top left and moves to the right sliding behind the needle and past it around to the bottom of the swing. Then the hook travels back again the same way to its original position for a return oscillation. Bernina sewing machines built their superior reputation based on their advanced oscillating hook system called a CB Hook.
Both systems do essentially the same thing. As the point of the 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 above the eye and amplified by a space called the scarf which is cut out above the eye. The point of the hook snags the thread from behind the needle and pulls it around the bobbin thread. As the needle rises, the threads are tightened into a lockstitch.
In both cases, the action of the hook must precisely synchronize with the needle. Even slight variations cause problems. This synchronization is known as hook-needle timing. If you see skipped stitches, bad stitches, or none, check the hook-needle timing.
In about twenty percent of all standard sewing machine services, the hook-needle timing will need to be set. So, get use to this adjustment. It will be frequent. The cause of faulting timing can be traced mostly to user activity. Forcing the sewing machine to go beyond its intended use by pulling the fabric while sewing or sewing too thick a material is a common cause. Broken needles, wear and tear, Dirt, and debris are also common causes. To make this adjustment check your service manual for the model you are servicing. In time, you will gain confidence and do most adjustments without having to look them up.
As long as there are millions of people using sewing machines, people will need sewing machine repair. You may just be the person to meet their needs either as a hobbyist or as you own business.
At first, fixing sewing machines can be an overwhelming task. There are so many different makes, models, and designs to learn. When you look at sewing machines, they may all look alike. As soon as you start taking off the covers, you discover just how different they really are. The hook assembly is one of the things that every sewing machine user should and every technician must understand.
When you look at a sewing machine, one of the first things you need to identify is if the machine has an oscillating or a rotary hook assembly. They do much the same task on your sewing machine, but they do it very differently.
The Rotary Hook Assembly includes a hook that moves in a complete circle round and round. The hook slides behind the needle, and proceeds all the way around the bobbin carrier until it again slides behind the bobbin carrier. Singer sewing machines revolutionized the sewing world with their drop in rotary hook systems.
Where do you put the bobbin on this machine? I could be inserted in front, or top under the needle plate, or on the left end of the machine. If it is a top loading bobbin, the machine is usually a rotary hook machine.
If the bobbin is inserted in the left end of the sewing machine arm or on the front face of the sewing machine arm, it may be either a rotary or oscillating hook.
A rotary hook moves around in a continuous circular motion. An oscillating hook moves back and forth. How can you tell which type of sewing machine hook assembly you have?
To double check you thinking, does the point of the hook go all the way around the carrier (Rotary Hook) or only part way (Oscillating Hook)?
The Oscillating Hook Assembly involves a hook that begins a few millimeters to the top left and moves to the right sliding behind the needle and past it around to the bottom of the swing. Then the hook travels back again the same way to its original position for a return oscillation. Bernina sewing machines built their superior reputation based on their advanced oscillating hook system called a CB Hook.
Both systems do essentially the same thing. As the point of the 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 above the eye and amplified by a space called the scarf which is cut out above the eye. The point of the hook snags the thread from behind the needle and pulls it around the bobbin thread. As the needle rises, the threads are tightened into a lockstitch.
In both cases, the action of the hook must precisely synchronize with the needle. Even slight variations cause problems. This synchronization is known as hook-needle timing. If you see skipped stitches, bad stitches, or none, check the hook-needle timing.
In about twenty percent of all standard sewing machine services, the hook-needle timing will need to be set. So, get use to this adjustment. It will be frequent. The cause of faulting timing can be traced mostly to user activity. Forcing the sewing machine to go beyond its intended use by pulling the fabric while sewing or sewing too thick a material is a common cause. Broken needles, wear and tear, Dirt, and debris are also common causes. To make this adjustment check your service manual for the model you are servicing. In time, you will gain confidence and do most adjustments without having to look them up.
As long as there are millions of people using sewing machines, people will need sewing machine repair. You may just be the person to meet their needs either as a hobbyist or as you own business.
About the Author:
Discover the secrets of repairing sewing machines Dr. David Trumble. Check out his extensive curriculum of sewing machine repair courses. Pick up your own free copy of his beginning course 7 Steps To Peak Performance For Your Sewing Machine.
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