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Bobbin threading on a sewing machine takes two steps: wind thread onto an empty bobbin using the machine's bobbin winder, then insert the bobbin in its case so the thread unwinds in the direction shown on your machine, and draw the thread through the tension slot. On a top drop-in machine, the bobbin sits under a clear cover on the needle plate. On a front-loading machine, it goes into a removable bobbin case under the free arm.
Most bobbin trouble comes from three things: a badly wound bobbin, a bobbin in backward, or the wrong bobbin class. Here's how to get all three right, with the manufacturer's rules wherever they matter.
Bobbin Threading on a Sewing Machine: What You Need
- An empty bobbin of the right class for your machine (see the chart below)
- The same thread you'll sew with, or a matching all-purpose thread
- Your machine's manual, or the threading diagram printed on the machine
Step 1: Wind the Bobbin
These steps follow the pattern in Brother's operation manuals and apply to most home machines. Your machine's printed winding path is the final word.
- Place the empty bobbin on the bobbin winder spindle, lining up its notch with the small spring on the shaft, and push the spindle into winding position until it clicks. (Brother bobbins have a notch for consistent winding.)
- Put the thread spool on the spool pin and add the spool cap so the spool can't wobble.
- Follow the bobbin-winding thread guides printed on the top of the machine. On Brother machines, the thread passes under a guide, then wraps counterclockwise under the pretension disc. Pull it all the way in so it sits under the disc. This disc is what makes the bobbin wind tightly and evenly.
- Wind the thread end clockwise around the bobbin five or six times by hand. Brother notes that winding clockwise stops the thread from wrapping around the winder shaft. Many machines have a small cutter slit in the winder seat to trim the tail.
- Start winding with the pedal or the start/stop button. If your machine has a speed slider, a medium speed gives the most even result. Brother recommends a low speed for stretchy threads like transparent nylon.
- Stop when the bobbin is full or when winding slows down. Many machines stop on their own.
- Cut the thread, push the spindle back to sewing position and remove the bobbin.
SINGER adds two rules worth following: wind only empty bobbins, never adding thread to a partly wound one, and don't overfill. Discard any bobbin that's chipped, bent or warped.
What a good bobbin looks like
A well-wound bobbin is firm, even from top to bottom and not overfilled past the rim. If it's soft and spongy, or thread is piled at one side, unwind it and wind again. The thread probably missed the tension disc.
Step 2: Insert a Drop-In (Top-Loading) Bobbin
Drop-in bobbins are the easiest to use, and they're on most current beginner machines from Brother and SINGER. Here's the sequence from a Brother manual:
- Raise the needle to its highest position (press the needle position button or turn the handwheel toward you).
- Raise the presser foot lever. On computerized machines, Brother also has you lock the keys so the machine can't start by accident.
- Open the bobbin cover by sliding the latch, and lift the clear cover off.
- Drop in the bobbin so the thread unwinds in the direction your machine shows. Brother's manual says to place it so the thread unwinds toward the left.
- Hold the bobbin down lightly with one finger, and guide the thread around the tab on the needle plate. Brother warns that if you don't hold the bobbin, the thread can break or the tension can be wrong.
- Draw the thread through the slit in the needle plate. This seats it in the bobbin case tension spring. Many machines have a cutter at the end of the slit to trim the tail.
- Replace the cover.
On Brother's Quick-Set machines, you can start sewing without pulling the bobbin thread up first.
Step 3: Insert a Front-Loading Bobbin
Front-loading bobbins sit in a metal bobbin case that clips in under the free arm. You'll find this system on machines like the SINGER M1500 and the Janome 2212.
- Raise the needle to its highest position and turn off the machine.
- Remove the free-arm cover or storage compartment to reach the hook area.
- Pull the bobbin case out by its hinged latch.
- Place the bobbin in the case in the direction your manual shows. The thread direction matters here just as much as on a drop-in.
- Pull the thread into the slot in the side of the case and under the tension spring, until it comes out of the small opening. You'll feel a light click as it seats.
- Leave about 4 inches of tail, hold the case by its latch, and push it fully onto the center pin until it clicks into place.
Pull up the bobbin thread
Front-loading and older machines usually need this step:
- Hold the top thread lightly with your left hand.
- Turn the handwheel toward you one full turn, so the needle goes down and comes back up.
- Pull the top thread gently. A loop of bobbin thread will come up through the needle plate.
- Pull both threads under the presser foot and toward the back.
New to the parts names? Our parts of a sewing machine diagram shows the bobbin case, hook and needle plate.
Bobbin Types: Which One Does Your Machine Take?
Sewing machine bobbins look similar, but they are not interchangeable. SINGER's bobbin guide lists the main home-machine types:
| Bobbin | Size (height x diameter) | How to recognize it | Notes |
|---|---|---|---|
| Class 15 (transparent) | 12 mm x 21 mm | Flat top and bottom, clear | Not interchangeable with Class 15 metal or 15J |
| Class 15J | 11 mm x 20 mm | Very slightly curved, slight blue tint | Not interchangeable with Class 15 |
| Class 15 (metal) | 12 mm x 21 mm | Flat top and bottom, metal | Only for models that come with metal |
| Class 66 (transparent) | 10 mm x 21 mm | Curved top and bottom, clear | Not interchangeable with Class 66 metal |
| Class 66 (metal) | 11 mm x 21 mm | Curved top and bottom, metal | Specific models only |
Source: SINGER bobbin selection guide. SINGER also lists special bobbins for specific older models, such as the Featherweight 221 and 222.
A few brand examples:
- SINGER: many current models, including the M1500, Heavy Duty 4423 and M1000, use SINGER Class 15 transparent bobbins.
- Brother: genuine Brother bobbins, like the SA156, are clear plastic and 7/16" deep, with a notch for consistent winding. Brother says the clear plastic lets the bobbin thread sensor work on machines that have one, and lists compatible models on each bobbin's page.
The rule: use the bobbin class your manual specifies, and ideally the brand's own bobbins. A bobbin a fraction of a millimeter off can cause skipped stitches, tension trouble and jams.
Common Mistakes (and How to Avoid Them)
- Inserting the bobbin backward. The thread must unwind the way your machine's diagram shows. If it doesn't, you'll get loose or looped stitches.
- Skipping the tension slot. On a drop-in, the thread must go around the tab and through the slit. On a front-loader, it must sit under the case's tension spring.
- Using the wrong bobbin class. Class 15 and Class 66 look alike but don't fit the same machines.
- Topping up a half-full bobbin. Wind only empty bobbins.
- Overfilling. An overfilled bobbin rubs in the case and creates drag.
- Winding without the tension disc. A soft, loose bobbin causes uneven stitches.
- Not holding the bobbin while threading. On a drop-in, light pressure keeps it seated.
- Ignoring lint. Fluff in the bobbin area causes skipped stitches. Brush it out every few bobbins. Our guide to sewing machine oil and maintenance covers cleaning.
Troubleshooting Bobbin Problems
| Problem | Likely cause | Fix |
|---|---|---|
| Bird's nest of thread under the fabric | Top thread missed the tension discs | Rethread the top with the presser foot raised |
| Bobbin thread showing on top | Top tension too tight, or bobbin inserted wrong | Reinsert the bobbin; test tension on scrap |
| Bobbin thread keeps breaking | Bobbin wound unevenly or wrong class | Rewind; use the correct class |
| Machine won't pick up the bobbin thread | Needle not fully up, or thread not in the slot | Reinsert the bobbin and pull up the thread |
| Clicking or jamming at the hook | Damaged bobbin or lint buildup | Replace the bobbin; clean the bobbin area |
For more, see our sewing machine troubleshooting guide, and the threading basics in how to use a sewing machine.
FAQ
Which way does the bobbin go in?
It depends on the machine, so follow the diagram on the needle plate, the bobbin cover or in your manual. On Brother drop-in machines, for example, the manual says to place the bobbin so the thread unwinds toward the left, then guide the thread around the tab and through the slit in the needle plate. A bobbin inserted the wrong way round is a common cause of loose, loopy stitches.
Are all sewing machine bobbins the same?
No. Class 15, Class 15J and Class 66 bobbins look alike but differ in height and shape, and SINGER states they are not interchangeable. Using the wrong class causes tension problems and jams. Always use the bobbin class listed in your manual, and ideally the brand's own bobbins.
Do I need to pull up the bobbin thread?
Not always. Many modern drop-in machines, including Brother's Quick-Set bobbin models, let you start sewing without pulling the bobbin thread up first. Older and front-loading machines usually need it: hold the top thread, turn the handwheel toward you one full turn, and pull up the loop of bobbin thread.
Why is my bobbin winding unevenly?
Uneven winding usually means the thread skipped the bobbin-winding tension disc, or the bobbin wasn't pushed fully onto the spindle. Rethread the winding path so the thread sits under the pretension disc, start the bobbin with a few clockwise turns by hand, and wind at a steady medium speed.
Can I wind a bobbin with thread already on it?
SINGER advises winding only empty bobbins and not adding thread to a partly wound one. Mixed or layered thread can wind unevenly and cause tension problems. Use the leftover thread for hand sewing or basting, or unwind it before reusing the bobbin.
Still Choosing a Machine?
A clear top drop-in bobbin is one of the most beginner-friendly features you can have. Every machine in our best sewing machines for beginners list explains its bobbin system.