Understanding Different Bobbin Sizes

Whether you work with different sizes and types of sewing machines on a regular basis or you are simply buying extra bobbins for your home sewing machine, it is important to know about the different bobbin sizes. ZJ explains about several of the different bobbin sizes, what machines they work in and how using the wrong size can affect your stitch quality.

Understanding Bobbins Sizes

Similar to many sewing tools, bobbins come in many various sizes and styles. Some are labeled with letters, like an ‘M’ or ‘L’ bobbin, while other are numbers, like 15. Knowing what type and size of bobbin your machine takes is important. Not all bobbins are clearly labeled with their size or style, however your machine manual should tell you what bobbin size your machine takes.

ZJ shows several of the different sizes and explains what machines they are for. Larger bobbin sizes are typically for long arm quilting machines or some embroidery machines. These machines are stitching very fast, and if they used a small bobbin, you would constantly be changing one out.

Types of Bobbins

Bobbins not only come in different sizes, but also in metal as well as plastic, and empty as well as pre-wound. While machines can only use one bobbin size, whether it is plastic or metal does not typically matter, however consult your machine manual to be sure. When buying bobbins, you can either buy them empty and learn how to wind a bobbin or you can find them pre-wound.

ZJ explains that some machines have issues with pre-wound bobbins and you may find your stitch quality is not where you want it. Some pre wound bobbins also come with cardboard on both sides that may need to be removed. Whether you buy empty or pre-wound, it is important to buy the correct bobbin size.

9 Responses to “Understanding Different Bobbin Sizes”

1. Joy M Schneider March 22nd, 2023

   your site for bobbin info list “ZJ”. How do I find out what this is/what it means? I have some bobbins that I purchased for my Pfaff but am being told they are for a newer Brother or Baby Lock. The bobbins do not have any info indicating this. Please help… thank you, blessings and later gater,,,, joy

   Reply

2. Vanessa Burroughs-Rhodes May 25th, 2020

   I just bought a package of bobbins that were the correct size for my machine, but apparently were made so cheaply that my machine keep breaking the thread while sewing.

   Reply

3. Shirley Martin June 19th, 2019

   I just bought a Juki Kirei HZL-NX7. There is nothing in the manual that says what type of bobbin it takes. I have a number of brother machines and it looks like an SA156. When I look at web sites for ordering bobbins, the SA156 is showing as the correct bobbin for other HZL machines but it doesn’t list the NX7. Juki makes a clear bobbin but it has no class, number or size. Is it different then the SA156? Will an SA156 work with my new machine? Thanks

   Reply

4. Melanie Bent June 14th, 2019

   Looking to purchase an older Pfaff industrial 1245 but don’t know if I can use the cardboard pre wound bobbins like I’ve been using for years in my industrial Brother. I’m okay with buying a different size. Can you help me? or send me somewhere I can get answers?

   Reply

5. wayne killinger May 19th, 2019

   i have a japanese machine from the 60-70s, a Bradford Zig Zag. It takes a 20mm bobbin but the top and bottom are thin metal, making the inner width 9mm, instead of the standard 8mm. Thus the sensor arm on the machine cannot fit into a width smaller than 9mm. I need more bobbins and dont know what to get.

   Reply

6. margotbeebe January 24th, 2019

   Ticket 21861 My plastic “j” bobbins keep breaking, and the thread is a tangled mess and I end up tossing the broken bobbin and its thread. I asked Singer if there was a metal J bobbin that I could use, but they said only the plastic is right for my machine. Any thoughts or comments?

   Reply

   • Customer Service January 29th, 2019

     Dear Margot,

     Thank you for your patience. In response to your question-

     If that is what they say- I believe they would know best for their brand of machine. However you can get additional bobbins online that you could try in your machine. Also, check other issues- like ensuring that your machine is threaded correctly- as there could be an underlying issues.

     Cheers,
     Ashley
     National Sewing Circle Video Membership

     Reply

7. Patricia Watt August 31st, 2017

   Are all size 15 bobbins interchangeable? Metal and plastic? 15J vs. plain 15? My machine manualdoes not have the bobbin size anywhere. I read every word. So I was watching two different instructional videos on that model, and one said 15J, and the other said 15. I called the company, and also got an ambiguous answer. The girl who answered the phone said 15J and then corrected herself to 15. 15j came with the machine. Now I’m really confused. I’ve measured everything I can measure, and I can’t see any difference between them.. are they interchangeable?

   Reply

   • Customer Service September 8th, 2017

     Hello Patricia,

     Class 15 bobbins and size 15J bobbins are generally not always interchangeable as the 15J is slightly smaller. However, one of my personal machines uses class 15 bobbins and I accidentally purchased 15J bobbins for it. The only place this was an issue on my machine was on the bobbin winder- the class 15 bobbin wound just fine but the 15J just spun in place. The 15J that I purchased were pre-wound and using the bobbin straight from the package did not affect my sewing, however I just can’t rewind them.

     This being said- if 15J came with your machine that is the type you should use.

     Hope this helps!

     Cheers,
     Ashley NSC Video Membership

     Reply