To wind a bobbin, put the thread spool on the spool pin, run the thread around the bobbin winder tension disc, thread the end through the hole in the bobbin from the inside, seat the bobbin on the winder spindle, push the spindle across to engage the winder, and run the machine at a steady medium speed until the bobbin is about 80 percent full. The winder tension disc is what makes the thread lie flat and firm; a bobbin wound without it is loose and uneven and shows up later as loops under your seam.
What do you need to wind a bobbin?
- The right bobbin for your machine. Bobbins look alike but differ by a millimeter in height and diameter between brands, and a wrong one winds badly and sews worse. Your manual gives the class or part number.
- A spool of thread, and a spool cap of the right size if your machine has a horizontal spool pin.
- An empty bobbin. Do not wind new thread over an old one; the two layers behave differently.
- Your machine's manual open at the winding page the first time. The path is drawn on the top of most machines as a numbered line.
How do you wind a bobbin, step by step?
- Set the spool. On a horizontal spool pin, put the spool on so the thread comes off the back and fit the spool cap against it. On a vertical pin, put the spool on with a felt pad underneath if one came with the machine. The thread should pull off smoothly without the spool jumping.
- Follow the winding path to the tension disc. The path runs from the spool to a small disc or a hook with a spring, usually near the top left of the machine, then back toward the winder on the right. Pass the thread around the disc so that it is held between the plates; you should feel a slight drag when you pull. This disc is separate from the needle thread tension, and it is the step most often skipped.
- Thread the bobbin. Push the thread end through the small hole in the bobbin from the inside out, and hold the tail on top. Seat the bobbin on the winder spindle with the hole up, and lock it if there is a notch that engages a pin on the spindle.
- Engage the winder. Push the spindle to the right until it clicks, or swing the small stopper arm against the bobbin, depending on your machine. On most modern machines this also disengages the needle automatically. On older and mechanical machines, loosen the handwheel clutch, the inner knob on the handwheel, or set the winding switch so that the needle stays still while you wind. A needle moving up and down with no fabric under it is harmless for a moment but wears the hook and wastes thread.
- Start slowly, holding the tail. Press the pedal gently for a few turns while holding the thread tail so that the first layer catches, then stop and trim the tail flush with the bobbin. A tail left under the layers tangles when the bobbin runs down.
- Wind at a steady medium speed. Hold the pedal at an even, moderate pace. Watch the thread cross the bobbin: it should build up in flat, even layers from one flange to the other. If it piles up on one side, stop and check that the thread is in the tension disc.
- Stop at about 80 percent. Most machines stop on their own when the bobbin is full; if yours does not, stop before the thread reaches the rim. An overfilled bobbin does not turn freely in the case and jams.
- Cut and remove. Push the spindle back to the left, lift the bobbin off, cut the thread leaving 10 cm (4 in), and re-engage the handwheel clutch if you loosened it.
The whole thing takes a minute, and it is worth winding two bobbins of the same thread at once for any project longer than a tote bag.
How full and how firm should a bobbin be?
A good bobbin looks like a spool from a shop: the thread is smooth, firm and level across the width, and you cannot push a fingernail into it. Pull a length off and the thread comes away evenly with a light drag. A loosely wound bobbin feels spongy and the thread sinks into the lower layers; that is what produces sudden loops on the underside of a seam when the bobbin thread catches on itself.
Fill it to a few millimeters below the rim. On a standard class 15 or 66 domestic bobbin that is about 50 to 60 m (55 to 65 yd) of all-purpose polyester thread, enough for roughly 20 to 25 m (22 to 27 yd) of straight seam at a 2.5 mm stitch length.
What are the common bobbin winding problems and their causes?
| Symptom | Likely cause | Fix |
|---|---|---|
| Thread loose and spongy on the bobbin | Thread not in the winder tension disc | Rewind with the thread seated between the disc plates |
| Thread piled up at one end | Thread left the disc, or the spool cap is too small | Rewind; use the larger spool cap on a horizontal pin |
| Thread tangled under the first layer | Tail not trimmed after the first turns | Unwind, start again and trim the tail flush |
| Bobbin winds too fast and bounces | Pedal pressed fully | Wind at medium speed; a slow, even wind lies flatter |
| Needle moving while winding | Handwheel clutch not released, winder not engaged | Push the spindle fully across, or release the clutch on the handwheel |
| Bobbin will not turn or slips | Wrong bobbin size, or the pin on the spindle is not in the notch | Use the bobbin class in the manual; seat the notch on the pin |
| Thread breaks while winding | Old or weak thread, or a burr on the spool pin | Change the spool; check the pin for rough spots |
| Winder stops early | Full-bobbin stopper set too close | Move the stopper arm slightly away from the bobbin |
How do you insert the bobbin once it is wound?
Insertion depends on your machine, and the two systems load differently. A drop-in bobbin sits flat under a clear plate in front of the needle; the thread leaves the bobbin counterclockwise on most machines and is drawn into a slot and under a spring, following the arrows on the plate. A front-loading bobbin goes into a separate metal case with its own tension spring, which you then slot into the hook with the finger pointing up; the thread direction and the slot in the case are what matter there.
Both systems need the thread to run under their tension spring, and a bobbin inserted the wrong way round sews a loose, loopy line even when it was wound perfectly. Drop-in vs front-loading bobbin explains the differences and which to prefer, and sewing machine basics takes you from the wound bobbin through threading to a first seam. The bobbin glossary entry is the short version.
Common mistakes
- Winding over a half-used bobbin. The old thread is at a different tension and often a different colour. Keep a box of empties.
- Using a bobbin from another machine. It may fit the spindle and not the case. Buy bobbins by the part number in the manual.
- Hand-winding. A bobbin wound by hand is never as firm or as even as one wound on the machine, and it is where most stitching problems on a hand-wound bobbin begin.
- Filling to the rim. A bobbin that touches the case cannot turn freely.
- Confusing the two tensions. The winder disc only affects winding. If your stitch looks wrong after a correct wind, the thread tension is the next thing to look at, and thread bunching underneath is usually the needle thread, not the bobbin.
When should you buy pre-wound bobbins instead?
Pre-wound bobbins are wound by machine on cardboard or plastic sides, tightly and evenly, and they hold more thread than a home-wound one. They make sense for long runs in one colour, for embroidery and quilting, and for anyone who winds badly on an older machine. They come in standard classes, so check that the class matches your machine, and remember that they are usually in a fine polyester that may not match a heavy top thread. For garment sewing with changing colours, winding your own stays the cheaper and more flexible habit.