M-style Prewound Bobbins

Here's what quilters love about prewound bobbins: they save you precious quilting time and give you consistent results every single time. No more dealing with loose spots, tight spots, or that annoying thread bunching that sometimes happens when you wind your own. Each prewound bobbin is machine-wound with perfect, even tension from start to finish. Plus, they hold up to 70% more thread than you can typically fit when winding your own, which means fewer bobbin changes when you're in the zone. For longarm quilters working on customer quilts, this is a game-changer. You can focus on your quilting instead of stopping to wind bobbins. Many quilters tell us their stitch quality improved once they switched to prewounds because the tension stays so consistent. We often hear the biggest benefit is convenience and saving time.

Great question! Here's the truth: you don't have to match fiber types at all. No quilting rule says cotton must go with cotton or polyester with polyester. In fact, many quilters mix them all the time. You might use Dream Seam cotton prewound bobbins with Perfection or QuiltMaker on top and get gorgeous results. The real secret is using the correct needle size based on the top thread and balancing your top and bobbin tension so the stitches are even. Mix and match based on what your project needs, not arbitrary rules. Your quilt won't know the difference, and you'll have more flexibility in your thread stash.

Class 15 bobbins fit most home sewing and embroidery machines. Check your machine's manual or measure your current bobbin (Class 15 is approximately 11.5mm tall and 20.5mm diameter). L-style bobbins are the same diameter as Class 15 but shorter, fitting specific machine models. M-style bobbins are larger and designed for longarm quilting machines and some commercial embroidery machines. If you're unsure, bring your current bobbin to your local dealer or check your machine's specifications. Using the correct size keeps your tension balanced and prevents jamming.

The difference is bobbin size and machine compatibility. Class 15 bobbins are the most common size and fit most home sewing machines (check your manual to confirm). L-style bobbins are the same diameter as Class 15 but are shorter and fit some home sewing machines (check your manual to confirm). M-style bobbins are used in many commercial and longarm machines and are the largest of these three bobbin styles (also holding the most thread). Each prewound bobbin type is designed to fit specific machines, so always check your machine's manual or bobbin case to determine which size you need. Using the correct bobbin size ensures proper tension and prevents jamming or thread breakage.

YLI offers two prewound bobbin thread options: Precision 60 wt. polyester (lint-free, available in white and black) and Dream Seam 50 wt. cotton (100% Egyptian extra-long staple, available in natural/off-white and black). Precision prewounds are the most popular choice for machine embroidery and longarm quilting because the fine 60 wt. stays hidden and produces no lint. Dream Seam prewounds are excellent when you want cotton throughout your quilt or prefer natural fibers. Both options are available in Class 15, L-style, and M-style to fit different machines.