The M Size Metal Bobbin is the standard empty metal bobbin for longarm sewing machines that use M-style bobbins. Metal bobbins are wound on the longarm machine directly from thread spools, providing a lower-cost per quilt alternative to pre-wound bobbins when you have the time to wind your own. Metal bobbins are durable, reusable, and provide consistent thread delivery when wound correctly.
Product Details
- Size: M (Class M / 15J) — the most common longarm bobbin size
- Material: Metal — durable, reusable, provides stable thread tension
- Use: Winding custom thread colors on your longarm or domestic machine for M-style machines
- Compatible With: Longarm machines using M-style bobbins (APQS Millie, Lenni, Lucey, and many others)
Frequently Asked Questions
- When should I use metal bobbins instead of pre-wound Magna-Glide bobbins?
- Metal bobbins are the economical choice when you have specific thread colors that don’t match available pre-wound bobbins, or when you prefer to control your own bobbin winding. Pre-wound Magna-Glide bobbins offer consistency and time savings; metal bobbins offer flexibility and lower per-bobbin cost when wound from your own thread.
- How do I wind an M-style metal bobbin?
- Most longarm machines have a built-in bobbin winder. Consult your machine’s manual for the specific winding procedure. Consistent, even winding tension is critical for consistent stitch quality during quilting.
- Are metal bobbins reusable?
- Yes — metal bobbins are essentially indefinitely reusable with proper care. They should be stored in a case or container to prevent damage to the bobbin lip, which affects tension if bent or dented.
- What is the difference between M-size and L-size bobbins?
- M-style bobbins are the larger of the two common longarm bobbin sizes. L-style bobbins are smaller and fit different machine models. Always confirm your machine’s bobbin size before purchasing — using the wrong size will prevent the bobbin from fitting in the machine.
- How many bobbins should I keep on hand?
- For production studios, keeping 10–20 metal bobbins wound and ready ensures you never have to stop in the middle of a quilt to wind a replacement bobbin. Having wound bobbins in the colors you use most frequently minimizes downtime.

