In our Blog Post yesterday, we touched on the Pyramid of Sewing. Here is some knowledge we have gained over the past 12 years of studying bobbins and thread.
1. What makes a good bobbin thread? The exact same thing as what makes a good top thread -- quality. A bobbin may hold 135 yards of a very thin, low quality, loosely twisted polyester thread. The same size bobbin may hold only 45 yards of a fuzzy (linty), cotton thread. Don't decide solely on yardage. Choose your bobbin thread based on quality. Choose bobbin thread from thread you are familiar with and know to be quality. If you use prewound bobbins, make sure the thread is a quality product.
2. Are prewound bobbins OK to use?
Yes, if the thread quality is good. Prewound bobbins will usually hold more than a self-wound bobbin due to the precision winding of professional winding machines. The market is flooded with prewound bobbins. However, nearly all the advertising emphasis is placed on everything EXCEPT the thread. For example,
Is it a plastic bobbin or a cardboard-sided bobbin? (It does not matter.)
Is it a magnetic bobbin? (All our research and testing shows the tension setting has more influence than does a tiny magnet.
How many yards of thread are on the bobbin? More important than yardage is the quality of the thread.
3. My dealer/technician said that using prewound bobbins will void the machine warranty.
Absolutely wrong. He/she is misinformed. Most machine companies sell prewound bobbins. Many dealers/technician may discourage the use of prewound bobbins based on their experience of cleaning machines that used low quality thread on the prewound. A prewound bobbin with a quality thread is much better for the machine than a self-wound bobbin with junk thread.
4. What is the recommended polyester bobbin thread? A smooth, lint free, tightly twisted thread such as Bottom Line or So Fine! #50.
5. What is the recommended cotton bobbin thread? A high quality, low lint cotton (extra-long staple Egyptian-grown cotton) such as MasterPiece.
6. What bobbin style works in my machine? There are three main bobbin styles and approximately 75% of all machines are compatible with one of these.
Home Machines L-style and Class 15 (also known as A-style) bobbins are the most common.
Longarm machines All longarm machines are compatible with either M-style or L-style prewound bobbins.
Please see our Bobbin Compatibility List to determine if your machine is compatible with a prewound bobbin.
The diagram below shows dimensions for L-style, Class 15 (A-style), and M-style bobbins. Click here to view a larger image of this diagram.