The purpose of the bobbin
The purpose of the bobbin is to work with the needle to form stitches with balanced tension. For this to happen, it must be the correct size for your sewing machine. It must be wound so the thread is tight and even, and then inserted correctly with the thread being pulled in the right direction to form the stitches. Now you know the purpose of the bobbin. Read on to understand how to do your part in making it happen.
size
The size of the bobbin for your sewing machine was established by the manufacturer. They may be interchangeable with other models/manufacturers, but it is not a one size fits all. There are numerous sizes; some are identified with a number; some are identified by a letter. For the best stitches and less problems, the manufacturer size identified with the model of sewing machine is the one to give the best stitches. My research revealed the most common sizes in the US are A (also known as Class 15), L, and M.
bobbin construction
Bobbins are constructed of either metal or plastic. Prewound ones may have cardboard sides and will be identified by size (Class 15 or A, L, M). Prewounds come tightly wound and sold in multiples. I have seen them in some quilting shops and retail sewing machine stores. They are also sold online. The benefit of prewound is not having to stop and wind one while in the middle of near the end of a project. Or, to have a good supply wound for your machine, you must have extras to pre-wind before starting a project.
shopping
Size is the most key factor when shopping for bobbins. The ways I know to get the exact size for your model are from the manufacturer’s representative stores, or reputable online sellers. Beware the online seller may sell you generic ones identified to fit your machine, much like those sold in big box stores. The list on the packaging of what machines the bobbins will fit is often the manufacturer name, not specific models. I have bought some of these but can’t say I have always been pleased with the performance. Side-by-side with my bobbin that came with my machines look the same, but performance is the key. Even a small difference in circumference and/or height you can’t see in the side-by-side test, you may see in the stitches. Remember plastic bobbins do not go into bobbin cases.
winding the bobbin
This is where I will suggest you refer to your manual for the exact path from spool to winder. The path for the thread to reach the bobbin will include going through tension discs before reaching the winding mechanism. If you do not properly seat the thread in-between the discs, you will have a mess of thread that is not tightly wound. Do follow the manual instructions. Some of the machines have arrows on the machine body you can follow.
Before placing the bobbin on the winder, bring the thread through a hole in the bobbin side. Pull sufficient thread for you to be able to get a good grip on it when winding begins. Place the bobbin on the winder spindle with the threaded hole side up. Manual machines and some computerized ones will require you to either slide the spindle to the winder stop or have you turn the small wheel on the end inside the large wheel toward you which will disengage the connection with needle movement.
With a good grip on the thread coming from the bobbin, watch as the spool thread winds around and up and down on the bobbin for two complete up-down passes. Stop winding and cut the thread you were holding even with the top of the bobbin. This will keep your thread from being pulled over the edge of the bobbin, which may cause uneven stitches.
Next Lesson – threading the sewing machine
In Lesson #4 you will be threading your machine. You will go from spool to needle and install the bobbin. Have a scrap piece of fabric available to do some practice stitching. We will talk about what a perfect stitch looks like. You will be inspecting the stitches in anticipation of Lesson #5 Tension and Lesson #6 Needles.
A smooth cotton rag will be fine for this lesson. Soon you will be receiving a shopping list for a fun project and basic tools.
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