Here is a neat hobby that can turn into a real job or even a business. I am talking about sewing machine repair. There is a special thrill when a broken down sewing machine springs back to life almost like new " right in your hands. While there are challenges, it can also be loads of fun.
When you start tinkering with sewing machines, be ready to learn loads of information. There are literally thousands of different models and designs, but there are also some obvious similarities. One of the tricky areas of interest is the hook assembly.
A quick inspection of a sewing machine, and the technician can tell if the sewing machine hook assembly rotates or oscillates. These two types of mechanisms are very different, but perform the same basic function.
If your machine has a rotary hook system, it will continuously turn around. Turn the hand wheel and see it rotate. The way it works, is simple. As the needle starts back up, the hooks point catches the thread in the scarf (just above the back of the eye). It then draws the thread around the bobbin.
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)?
Watch closely. The point of the oscillating hook starts just a few millimeters to the left of the needle when it reaches its lowest point. As the needle rises, the hook moves behind the needle. A loop of thread forms in the small cut out on the back of the needle running above the eye called the scarf. The point of the hook grabs the thread here and pulls it around to the bottom where it releases the thread. It then oscillates back to its original position for another stitch. Bernina used their special patented CB Hook to become a premium sewing machine line.
As far as the user is concerned, it does not matter a lot whether the machine has an oscillating or a rotary hook. Both systems achieve the same basic result. The pick up the thread from the scarf of the needle and pull it to wrap around the bobbin thread.
The movement and positioning of the hook and needle must coordinate exactly. Slight variations result in skipped stitches, poorly formed stitches, or no stitches at all. The hook and needle travel 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 and at the right moment for the hook to snag the upper thread. This is called Hook Needle Timing.
Adjusting the hook-needle timing is a very common adjustment. If the user breaks a needle, sews on excessively thick material, or debris builds up in the gears; the timing often gets jolted out of adjustment. The specifics of making this adjustment vary considerably from one model to another. Some adjust on gears located directly below the hook. Some adjust at the side or at the end of the lower shaft. Some use timing belts. The essential adjustment is always the same, however, in that the point of the needle must reach the scarf at precisely the right time and in the right way. Check the specific service manual for details on adjusting the hook-needle timing until you gain enough experience and knowledge to adjust it on the fly.
The more you learn about how sewing machines work and how to repair them, the more sewing machine repair you can do. Just think there are millions of sewing machines just waiting to be serviced by somebody. You could be that somebody. - 16732
When you start tinkering with sewing machines, be ready to learn loads of information. There are literally thousands of different models and designs, but there are also some obvious similarities. One of the tricky areas of interest is the hook assembly.
A quick inspection of a sewing machine, and the technician can tell if the sewing machine hook assembly rotates or oscillates. These two types of mechanisms are very different, but perform the same basic function.
If your machine has a rotary hook system, it will continuously turn around. Turn the hand wheel and see it rotate. The way it works, is simple. As the needle starts back up, the hooks point catches the thread in the scarf (just above the back of the eye). It then draws the thread around the bobbin.
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)?
Watch closely. The point of the oscillating hook starts just a few millimeters to the left of the needle when it reaches its lowest point. As the needle rises, the hook moves behind the needle. A loop of thread forms in the small cut out on the back of the needle running above the eye called the scarf. The point of the hook grabs the thread here and pulls it around to the bottom where it releases the thread. It then oscillates back to its original position for another stitch. Bernina used their special patented CB Hook to become a premium sewing machine line.
As far as the user is concerned, it does not matter a lot whether the machine has an oscillating or a rotary hook. Both systems achieve the same basic result. The pick up the thread from the scarf of the needle and pull it to wrap around the bobbin thread.
The movement and positioning of the hook and needle must coordinate exactly. Slight variations result in skipped stitches, poorly formed stitches, or no stitches at all. The hook and needle travel 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 and at the right moment for the hook to snag the upper thread. This is called Hook Needle Timing.
Adjusting the hook-needle timing is a very common adjustment. If the user breaks a needle, sews on excessively thick material, or debris builds up in the gears; the timing often gets jolted out of adjustment. The specifics of making this adjustment vary considerably from one model to another. Some adjust on gears located directly below the hook. Some adjust at the side or at the end of the lower shaft. Some use timing belts. The essential adjustment is always the same, however, in that the point of the needle must reach the scarf at precisely the right time and in the right way. Check the specific service manual for details on adjusting the hook-needle timing until you gain enough experience and knowledge to adjust it on the fly.
The more you learn about how sewing machines work and how to repair them, the more sewing machine repair you can do. Just think there are millions of sewing machines just waiting to be serviced by somebody. You could be that somebody. - 16732
About the Author:
Get more detials on 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.