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Note: For questions regarding what style of bobbin your machine uses, please review our Bobbin Compatibility List here.

Q: Can I use BOBs in my sewing machine?
A: Most machines do not like the combination of the smooth thread and smooth plastic sides. Therefore, for machine use, we recommend SuperBOBs. SuperBOBs  use the same thread but have cardboard sides.

Q: What can I use BOBs for?
A: The three Assortment Sets are fantastic for hand applique and hand binding. You have a variety of 36 colors instantly at your fingertips in a convenient, resealable case.

Q: I have L style prewound bobbins and have a problem with the bobbin catching in the bobbin case. It seems like the paper sides on the top and bottom of the bobbin are just a little too wide in circumference. Will these not work in my machine?
A: Remove the cardboard sides.  They are made to be removable.  The thread will not unravel.

Q: Are L style bobbins the same as Class 15?
A: No. Although the bobbin diameter is the same, Class 15 bobbins (Janome machines) are a little taller.  Some Class 15 bobbin machines can use L style bobbins but not vice versa.

Q: Why should I use prewound bobbins when I can wind my own?
A: Good prewound bobbins are wound by high tech machines which provide a smooth, uniform wind. The result is much more thread on the bobbin than a self-wound bobbin. Whether you're in the middle of an embroidery design or a quilting or sewing project, having to stop to change the bobbin is always an inconvenience.

Q: What does L style and M style mean?
A: These are the two most common sizes of prewound bobbins. Some longarm machines (A-1, Gammill, Handi Quilter, Homesteader, some Noltings) use the M size, which is the larger bobbin. Some longarm machines (APQS, some Noltings) use the L style bobbin. Approximately 75% of home machines use the L style. The trend is moving toward more compatibility as most home machine manufacturers are making their machines compatible with the L style bobbin.

Q: Is there a difference between plastic sided and cardboard sided bobbins?
A: Either type is fine. Plastic bobbins are reusable; cardboard bobbins are disposable. Because the plastic-sided bobbins are so smooth, they may continue to spin even after your machine stops and cause backlash. Some machines seem to work better with the cardboard-sided bobbins because the cardboard sides provide more friction and backlash is usually not a problem. If it is, the bobbin tension may need to be tightened.

Q: Should I use a polyester or a cotton bobbin thread?
A: It's a matter of personal preference. Polyester has very little or no lint. Cotton prewound bobbins will throw off lint and will require more frequent machine cleaning. Watch our video on Cotton and Polyester threads and see the differences between the threads.

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

Q: How much thread does my bobbin hold? 
A: There is a major difference between a self-wound bobbin and a professionally wound prewound bobbin. Even among self-wound bobbins, there will be differences due to machine winding tension settings, speed, and size of thread. Here are estimates: 

L style Bobbin

Bottom Line: 118 yds.
Masterpiece: about 80 yds.
Brand X cotton: 39 yds.
So Fine: 66 yds.

M style Bobbin
Bottom Line: 215 yds.
Masterpiece: 148 yds.
Brand X cotton: 71 yds.
So Fine: 120 yds

Q: Why are there cardboard-sided, plastic-sided, metal-sided bobbins?
A: 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.

Q: Should I remove the cardboard sides? 
A: 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. 

Q: Is there a top side and bottom side to a bobbin? 
A: 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.

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

Q: Why use a colored bobbin thread?
A: 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.

Q: I'm a long arm quilter, and I use King Tut thread just about all the time. I love this thread ! The problem is every time I use the black or linen color thread it breaks as I'm trying to quilt. It will break several times per row of quilting. I have no problem with any other color. I have try everything, new needle, re-threading the machine, adjusting the tension. I also use Longarm Machine Needles Size19 4.0. 
A: Let's start with the bobbin tension. Take out the bobbin case and turn the tension screw 1/2 turn to the left (counter clockwise). Then loosen the top tension more than you think would be necessary. Once both top and bobbin tensions have been loosened, please try this thread again.

Q: I really like the Superior Masterpiece pre-wound bobbins but I have tried to use several which simply do not feed through my bobbin. What is the cause of this? I have no other choice but to rewind the thread on to my regular bobbins thus defeating the purpose of having pre-wounds.
A: Remove the cardboard sides and they should work better.

Q: I am having trouble with tensions. Do you believe it possible to have a stitch balanced so that one does not see a dot of bobbin thread on top? I am having most trouble with the So Fine #30. I love them but always see quite a lot of bobbin thread. 
A: Yes, it should be possible. If you are seeing the bobbin thread on the top, the top tension is too tight and therefore it is pulling up the bobbin thread. Reduce the top tension to about a 2.0 or 2.5 range and that should make a difference.

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By: Bob Purcell