Superior Threads

Bobbin University | All About Bobbins

1. Why are there cardboard-sided, plastic-sided, metal-sided bobbins?

It doesn't matter whether the bobbin is made of metal, plastic, or paper as long as there is sufficient strength to hold the thread. Plastic has improved over the years and is much less expensive than metal so most machine manufactures now offer plastic bobbins with their machines. Although most brands make their own plastic bobbins, 70% of machines now use the generic L size bobbin and it is not necessary to buy brand-specific bobbins. If your machine uses the L size bobbin, you can use either your machine brand bobbin or generic plastic or cardboard-sided bobbins. Pay more attention to the quality of thread on the bobbin than whether the bobbin is cardboard-sided or plastic or metal. Both the metal and plastic bobbins are reusable.

L-size cardboard-sided bobbins are the original standard. L-size plastic-sided bobbins have the same diameter and core size, but some are slightly taller. The advantage here is that it holds more thread. If the bobbin case is designed to hold a taller plastic bobbin and you want to use a paper-sided prewound bobbin because that has the thread you want, it will probably work but you may get some play or bounce in the bobbin. To correct this, stack one or two layers of the torn away cardboard sides underneath the bobbin to raise it up.

2. Should I remove the cardboard sides?

Do I need to remove the paper-sides on the cardboard-sided bobbins? The main reason to remove the cardboard sides is to allow machines with low bobbin thread warning light sensors to work. If your machine doesn't have a low bobbin thread sensor, there is no reason to remove the sides, so leave the sides on because it will usually fit better in the bobbin case. Machines are sometimes brought in for service because the low bobbin thread sensor no longer works. Sometimes it's as simple as making sure the bobbin cover door is closed during use so that the sensor light is aimed in the proper direction. If you sew with the bobbin cover open, your machine will work but the sensor will not. Some people prefer to turn off the auto sensor when using prewounds. A self-wound bobbin may have only a few feet of thread left when the bobbin sensor light comes on, so the warning must be heeded. However, for those who use prewound bobbins, the wind is usually much more compact and accurate and when the sensor beeps, there still might be 10 yds of thread left on the bobbin. If your machines stops at the low-thread warning, just turn off the low bobbin thread warning sensor and sew until it runs out.

3. Is there a top side and bottom side to a bobbin?

Yes, there is a top side. If your machine specifies that the thread needs to unwind with the bobbin rotating in a clockwise direction, hold a bobbin flat in your left hand and pull the end of the thread with your right hand, unwinding the bobbin. As you unwind the bobbin, the bobbin should rotate in a clockwise direction. If the bobbin is rotating counter-clockwise, turn it over and the direction will reverse. By properly placing the bobbin in the bobbin case, the bobbin system can work as designed. If you use machine-branded bobbins, the logo mark on the bobbin is usually the top side.

4. Why are there L-size, M-size, A-size, Class 15, and other brand-specific sizes?

Machine manufacturers make what they believe is the best bobbin for their respective machines. Some are made to fit only their machine and are not interchangeable with other machines, while others make a common bobbin type which is interchangeable with other machines. Some bobbins have holes in the sides. The advantage to this is that you can reuse a plastic-sided bobbin with holes because it is easier to get the wind started. If a bobbin type is exclusive to a specific machine, generic bobbins generally do not exist. Don't choose a new machine based only on the bobbin type, but if your machine uses one of the more popular sizes, you have an added bonus of being able to use prewound bobbins.

5. Are prewound bobbins OK to use in my machine? Will using them void my warranty?

Prewound bobbins are OK to use on your machine. The horror stories we hear about are not with the bobbin, but with the quality of thread. As with other products, there is large range of quality in bobbin thread. If you found a bargain on the Internet for a huge box of prewound bobbins for $9.00, you will probably get a very low quality, linty, loosely twisted thread that will do more harm than good. Although we often hear stories of customers being told that using prewounds will void their warranty, that is not true. That would be like saying using a low-octane gasoline will void your car warranty or using inexpensive film will void the camera warranty. The results will most likely not be what you wanted, but it won't void the warranty unless it is clearly stated in owner's manual or on the warranty card. By choosing good quality over fantastic Internet bargains, you will make sure your machine will operate as intended and stay in good condition.

6. Why use a colored bobbin thread?

A perfect stitch is sometimes hard to achieve and therefore the bobbin thread may show on top. A white or black bobbin thread is high contrast and therefore can be visible. By matching the color of the bobbin thread to the top thread, the bobbin thread will blend. Then, if the bobbin thread does show a little on top, it will not be visible.

More Bobbin Thread Education

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