This:
Is not your enemy.
I know there are days…days when you can’t seem to sew a single stitch without puckers, or seams that are too loose, or your thread constantly breaks. You check your machine, thread it, and re-thread it. You situate your spool so the thread runs horizontally…then vertically…
And nothing works. After you’ve checked and re-checked everything, it’s easy to blame all your sewing machine’s bad behavior on a little metal or plastic disk. However, most of the time, the poor bobbin is truly an innocent bystander and it’s something else giving you thread issues.
To start, let’s take a look at what a bobbin is and its function in the sewing machine. By definition, a bobbin is “A spindle or cylinder, with or without flanges, on which wire, yarn, thread, or film is wound. Bobbins are typically found in sewing machines, cameras, and within electronic equipment. In non-electrical applications the bobbin is used for tidy storage without tangles. Typically, as quilters, when we throw the term “bobbin” around we’re talking about the plastic or metal disks which are used in the bobbin case of our machines and allows us to make a lockstitch. However, from this definition, bobbins are also used in other types of machinery. Remember when we actually used film in cameras? The film was wound around a plastic or metal cylinder called the film bobbin. And if you are like me and are from an area where textile manufacturing was prominent before NAFTA, you may have seen some of these around:
These are yarn bobbins used in fabric manufacturing.
Those large, wooden spool-like things on the back of this truck? Also bobbins. These bobbins are used to store cable, wire, hoses, etc., as it’s transported and warehoused.
As avid sewists, it’s important to know the kind of bobbin your machine takes and why the correct size is crucial. There are 10 different types of them:
Class 15 or A Style – This bobbin is about the size of a nickel and the top and bottom are completely flat. It comes in both plastic and metal.
L-Style – This bobbin is also about the size of a nickel. It’s flat and narrow and available in plastic, metal, aluminum, and as a magna-glide core.
M-Style – This bobbin is about the size of a quarter. It is large and flat and available in metal, aluminum, plastic, and as a magna-glide core.
Two asides at this point. First, you’re probably wondering what a magna-glide core is. This is the term used for a pre-wound bobbin which has a magnet in it to help it stay anchored in the metal bobbin case used in front loading machines (more about these in a bit). Second, the majority of household sewing machines use one of these three bobbins. It’s also worth noting that L-Style bobbins are the same width as Class 15 bobbins. This means you can use a L-Style bobbin in your Class 15 machines. However, a Class 15 bobbin is too tall to fit in an L-Style sewing machine.
The next seven bobbins are less common, but it’s nice to know about them.
Singer 163131 – This is about the size of a quarter and can be disassembled by unscrewing the bottom to quickly remove unwanted thread. This bobbin is only available in plastic.
Singer 8228 – This is the bobbin used in most treadle machines. It’s available only in metal.
Class 15J – About the size of a nickel, this bobbin looks similar to a Class 15, but has just a slight curve on the top and bottom. It’s available in metal, plastic, and aluminum.
Class 66 – This bobbin is also about the size of a nickel and has a curved top and bottom. It comes in plastic, metal, and aluminum.
Bernina 0115367000 – This bobbin is commonly used in the older Bernina machines. It’s also about the size of a nickel and is available only in metal.
Juki 270010 – These are the most common Juki specific bobbins and are very similar to the L-Style bobbins. These are also the size of a nickel.
Viking Specific 4125615-45 – This bobbin is a Husqvarna Viking specific, nickel-sized bobbin. It fits all machines in groups 5, 6, and 7 – mostly the newer machines.
If you truly think it’s the bobbin which is giving you problems, make sure you’re using the right bobbin for your machine. Consult your manual or use Google to find out what kind of bobbin your machine takes and use that size. Some machines, such as the Viking Specific 4125615-45 above, is brand-specific – it only works in a particular group of Husqvarna Vikings. If your machine is one of those which must have brand-specific bobbins, be sure to use them. And here’s a little extra tidbit about bobbins – there really is no difference between plastic and metal bobbins. Years ago, there was a big difference between the two because the plastic was inferior and would crack or become brittle as the bobbins aged. Today’s plastic is much better, and these bobbins work just as well as their metal counterparts.
Many times, it’s not the bobbin itself giving you issues, but the way the bobbin was threaded. Be sure the thread is wound evenly and there are no bulges. The bobbin thread shouldn’t be spongy feeling, either. If you wind a bobbin and the tension isn’t even or it has more in one area than another, the best piece of advice I can give you is unwind it and start over.
And honestly, the correct bobbin and a correctly wound bobbin are the two biggest bobbin issues. Most sewing/thread problems don’t involve the bobbin, but the bobbin case. To understand those issues, it’s important to recognize the two types of bobbin cases. There’s the front-loading machine:
Which loads the bobbin in one of these:
A metal bobbin case, which is inserted in the front of the machine.
Then there’s the top-loading machine:
In these machines, the bobbin case is plastic and lies horizontally beneath the feed dogs.
These bobbin cases tend to stay in the machine, and only the bobbin itself goes in and out.
Each of these types of bobbin cases can have their own unique issues; however, there are some common problems with the two.
- The Bobbin Case Won’t Turn – There could be two reasons for this. First, your tension may be too tight. Simply readjust your tension and keep checking the bobbin case. A slight tweak of the tension may be all that’s needed. Second, the bobbin may be unevenly threaded. If this is the case, just wind another bobbin. It’s important to remember winding a bobbin is not a race. A slow wind, at an even pace, usually assures even winding.
- Bobbin Case Stuck in the Machine – Sometimes this is an easy fix and sometimes it’s not. The first step is to carefully examine the bobbin case and see if it needs cleaning. With the case for a front-loading machine, this is pretty easy. The metal case itself can be looked over quickly as well as the place where the bobbin case rests. Top-loading machines take a bit more time, as the metal plate beneath the presser foot has to be removed before you can get at the bobbin case. With both types, examine the case to see if there is any stray threads or lint build up which may prevent the bobbin case from moving. After you’ve cleaned the area, if the bobbin case still won’t move, then it’s time to call the machine tech. At this point, they need to figure out what’s wrong.
- Loose Bobbin Case – Call a tech. Don’t try to take care of this problem yourself.
- Bobbin Case/Bobbin Thread Jams – Both of these problems are the result of the same issues. First, you may need to oil your machine (if it requires oiling – some of the new models do not). Second, you may need to clean your machine. Third, it’s not threaded correctly, and fourth the tension is wonky. Taking care of any or all of these may solve the jamming issue. If not, make sure you’re using the right bobbin for your sewing machine. It’s easy for those of us with multiple machines to get the bobbins mixed up. One final reason for the jamming may be that you started sewing on the edge of your fabric and knots have already formed, jamming your machine.
- Bobbin Tension Repair – This is way easier to fix than it sounds, but it only works with those machines which use a metal bobbin case like this:
On the side of the case should be a tiny screw. In quarter-turn increments, turn the screw counterclockwise to loosen the tension and clockwise to tighten it. Sometimes you can also help the tension issue out by adjusting the tension on your needle thread. If your bobbin needs to work a little more, lessen the needle tension up a tad. Tighten it if the bobbin needs to work less.
- Make Sure The Bobbin is Inserted Correctly – Most bobbins have a top and bottom and need to be inserted according to the directions in your sewing machine’s manual
- Make Sure You’ve Disengaged the Machine’s Bobbin Winding Mechanism – With many machines, there’s some type of lever you have to move to get the sewing machine out of bobbin winding mode and back into the regular sewing mode. New machines may do this automatically once the bobbin is filled (my M7 Continental does)
One last word about the bobbin and the bobbin case. Over a period of time and use, the case and bobbin may develop burrs. To check, run your pinkie finger over them. If you feel any rough spots, it’s time for a new case or a new bobbin or both.
But what if you’re pretty certain your issues aren’t with the bobbin or the bobbin case? If you’re still experiencing stitch issues, there is a standard checklist you can run down.
- Clean your machine. I think I’ve mentioned this three or four times in today’s blog. Just remember a clean machine is a happy machine which performs well, runs smoothly, and doesn’t make weird sounds. You should clean your machine according to your manual regularly and at least once a year take it into a tech for a deep clean and oiling in all those places you can’t reach.
- Rethread the machine. Honestly, this is my first line of defense. Most of the time – I’d safely say 80 percent – this is my problem.
- Change the needle. Needles have a usage life. Even if they seem to be sewing fine, after about eight hours of sewing, a regular sewing needle should be tossed. If you’re using titanium, you can double the amount of time. Even if the needle appears just hunky-dory, eight hours of steady sewing can cause slight bows in the needle. And don’t forget this picture:

The needle on the left is a new needle. The picture on the right is the same needle after eight hours of sewing. You can see how the needle degrades over time and use until the sharp tip has been worn smooth. Instead of penetrating the fabric, it pokes holes in it.
I can’t emphasize this enough: MAINTENANCE IS YOUR MACHINE’S BEST FRIEND. It solves most of your sewing issues and prolongs the life of your machine.
I really hope this helps you with any machine problems which may crop up. Nothing is more disheartening than sitting down to sew (especially after you may have looked forward to it all day) and have your machine develop an attitude. Most of the time it’s something small, but anytime you feel daunted by a problem, call your sewing machine tech. They can either re-affirm what you think is wrong and walk you through the fix or make an appointment for you to bring it in.
Until next week, Make Your Quilt Yours!
Love and Stitches,
Sherri and Sam