The belt is the main part of your sewing machine. This is what drives the wheel and makes your machine sew.
In the earlier manual sewing machines, the belt connects the band wheel, which is the large wheel at the bottom with the handwheel at the top.
When you work your foot on the pedal, the larger wheel turns, and the belt makes the handwheel turn. In modern electric machines too, the mechanism is the same.
The belt connects the handwheel with the wheel at the motor. When the motor turns, the belt drives the handwheel, thus helping you sew.
Understanding Sewing Machine Belts
Though it sounds like a simple part to you, there are many types of sewing machine belts, and each one has different qualities. There are geared belts and non-geared belts for your machine. If your motor pulley is a toothed wheel, then you must use a geared belt.
This kind of belt doesn’t offer any room for adjustment. The other non-geared belts are used when the pulley is smooth. In such machines, you will have the facility to adjust and tighten the belt if there is any slack.
Types Of Non-Geared Belts
Among the non-geared belts, you have V-belts, lug belts, and round belts. The V-belts fit in a groove in the pulley and perform very well. The lug belts have a teethed inner side but not like the geared belts and cannot be used in teethed wheels.
The teeth are only for better hold. The round belts are round in shape and are stretchable to a certain extent. These can be used when you don’t get a V-belt or lug belt for your machine. Their performance is not up to the standard of the other two belts.
Precautions For Changing A Geared Belt
As you already know, a geared belt is made precisely to fit your machine. There is no room for any adjustment. Hence it must be installed very accurately, or you can throw the needle bar out of sync.
It would help if you marked the highest position of the needle and the corresponding position of the highest cog of the motor pulley. This way, you will know where they should be when you install the new belt. This will save you even if something moves when you are installing the new belt.
Finding The Right Non-Geared Belt For Your Machine
For most brands of machines, you can find the right non-geared belt from the various websites that are dedicated to sewing. However, in the rare event of not being able to get the correct belt for your machine, there is a method to find the exact measurements.
If the belt in your machine is outside, it is easy. If the motor is adjustable, then you must first position it in the middle of the slot.
Take the twine and wrap it around the handwheel exactly at the position of the belt. Bring the twine to the motor and take it around the pulley. Join both ends and mark the position with a pen.
Make it as tight as possible because new belts will slacken a little. When you cut the twine at the place you have marked, you have the exact size of your belt.
Measuring your old belt will not be correct as it would have already slackened, which is why you are changing it. Even if your belt is not outside, it will only take a couple of screws to be removed to reach the belt.
Removing Your Worn-Out Belt
Some care should be taken before you remove your belt. The first thing to do is to remove the plug from the electrical socket. You must also ensure that the handwheel is disengaged. This will prevent the needle from moving when you are removing the belt.
You must then remove the screws at the back of the sewing machine, which holds the motor to the machine. You can then slip the belt from the pulley easily.
When you are removing the belt from the handwheel, care must be taken. You may have the turn the handwheel forward, and this has to be done very slowly. It could otherwise disturb the timing of the machine.
Installing The New Belt In Your Machine
You must first fix the new belt on the handwheel. You may need to turn the handwheel for this purpose. Carefully turn the wheel backward as you feed the belt. Ensure that you have the right side of the belt outside.
In most belts, it is easy to find because of the markings. Slowly feed the belt on the handwheel in the correct position. Take it down to the pulley of your motor.
When you slip the belt on the pulley, ensure that there are no twists in the belt. The new belt will be tight, and you may need to pull the belt a bit to fix it properly.
Completing The Installation Process
Once you have installed the belt, push the motor to the original position where the belt is at its tightest. This can be done in case the motor position is adjustable. This will ensure a tight fit for the belt as it tends to slacken a little later.
You must secure the motor by tightening the screws that hold the motor housing. You must check the slack of your belt once you have fixed the screws. The belt must not have a slack of more than half an inch.
Put back the covers that you removed and secure all the screws. You must then re-engage the handwheel. Turn the handwheel slowly and see if the needle is moving. Do it slowly so that you don’t disturb the timing. You can now connect the machine to power. Check that everything works perfectly.
Conclusion
While changing the belt in a sewing machine can be done without the help of a mechanic, it is better to study the manual very carefully before you start the work. You must understand the type of belt to be used and get the same one.
If you have a geared belt, you must get the same size. The numbers are usually mentioned on the belt. If it is worn out, the sewing machine manual should give the information.
If in case you cannot see the belt when you remove the side of the machine, then the machine has an internal belt. It is better to take the machine to a mechanic to fix the belt.