Prewound bobbins - do they fit my machine?

Prewound Bobbins – do they fit my machine?

Prewound bobbins have become popular with quilters and machine embroiderers, both because of their convenience and the ability of the manufacturers to get more thread on the prewound than you can wind at home.  Historically, there have been a LOT of different sizes of bobbins for domestic machines – the kinds of machines you use at home – but the good news is that manufacturers are standardizing their bobbin sizes over time.

Do you need prewound bobbins? Not necessarily, but you might like to try them.  And if you haven’t tried them lately, you might want to revisit prewounds to see if the product changes and improvements make your quilting life easier.

The most common sizes of prewound bobbins available to quilters are L Style, Class 15 (sometimes called A Style), and for some longarm machines, M Style.  L Style and Class 15 bobbins are small, M Style bobbins are much larger, about the size of a quarter.

Here is the most important thing that I want to say in this blog entry:  You need to know what size bobbin your machine takes.  Look it up in your manual, ask your dealer, or look it up online.  If you don’t think you’ll remember the size, write it down on something you carry all the time (like on the outside cover of your check register).

There are so many HUNDREDS of brands and models of machines that a retailer cannot possibly memorize them all and know which bobbin size fits yours.  There are charts of bobbins sizes here and there on the Internet and sometimes published in magazines, but the BEST thing for you to do is research it yourself and have that information ready when you buy prewound bobbins.

Older machines may have proprietary (meaning exclusive to that machine or brand) bobbin sizes.  Independent businesses that specialize in maintaining vintage machines are often able to order specialty bobbins.  But don’t necessarily expect that prewounds will be available for your vintage baby.

Prewound bobbins come with plastic or cardboard sides.  You might need to experiment to see which ones are best for you.  If your machine has a detection system that alerts you to a “low bobbin thread” situation, the detector needs to see the thread from the top.  The plastic bobbins are see-through; the cardboard ones are not.  Some people, finding that the cardboard ones are their preference, peel the cardboard top (or top and bottom) off the bobbin and use it that way.  The reason this is possible is that thread for prewound bobbins is treated with a starch product that holds the thread in place on the bobbin. 

Some people just find that the cardboard bobbins work better for them with one or both sides removed, regardless of the machine’s need to see the thread.

Bobbin tension

As you know, in most domestic machines tension is adjusted for the top thread but not for the bobbin thread.  There is a way to adjust bobbin tension for front-load bobbins by turning the TEENY screw on the bobbin case, but most quilters are afraid to do it.  Even the pro’s keep a spare bobbin case for adjusting and one where the screw is never changed. 

If you find that you need more control over your bobbin tension (especially for free-motion quilting), some of the prewound bobbins and accessory products are attempting to help you with that. 

Some smooth, plastic-sided bobbins have been accused of continuing to spin when you stop sewing, thereby creating what is called “backlash” and a resulting bobbin thread mess under your quilt.

There is a disc made of Teflon and shaped like a “washer” that can be placed beneath a drop-in bobbin; this theoretically increases the bobbin tension and manages “backlash”.  This is sold as the “Little Genie Magic Bobbin Washer” –in two sizes, one for domestic and one for longarm machines.

Another new type of bobbin uses a magnetic core to manage bobbin tension. 

Fiber Content

The current crop of prewound bobbins come in the most popular fiber contents:  Cotton, polyester, and nylon.  They also come in a variety of thread weights.  Read the packages carefully to make sure that you are buying the fiber and weight that will best oppose your top thread.  The newest prewound on the market is the Deco Bob from Wonderfil which is an 80-weight polyester thread similar to their amazingly popular Invisafil 100-weight thread.  These are manufactured in L Style, Class 15, and M Style plastic-sided prewounds and sold in a card of one dozen. 

Color

Prewound bobbins are not always made with the thread color you need to exactly match your top thread.  Even if they’re manufactured, they’re not always available from your retailer because of the vast number of thread colors and thread weights that they would need to carry.  So be prepared to choose a neutral or blending color for your prewound bobbin thread.

Still not sure?

Only your experience with prewound bobbins will tell you if they are compatible with your machine and if you even like them.  Buy a package and try them!  If they don’t work for you, pass them along to a friend.  Or begin by going together with a friend or two and buy a package – split them up and try them! 

There is a LOT to be said for experimentation.  I equate using a sewing machine to playing the violin; you must KNOW your instrument and how it will perform under varying circumstances and with a variety of accessories.  That comes down to practice, practice, practice.  Luckily, pushing that fabric through the machine is what quilters enjoy most!

Hand sewing with prewound bobbins

Yes, it’s true.  MANY hand-piecers and appliquérs buy prewound bobbins in a neutral color assortment for their carry-along sewing kit.  They’re not so much interested in the bobbin construction as in the thread.  When space is tight or several colors are needed for a block, hand-sewers snap up those variety packages of prewound bobbins. 

Threadmongers carries prewounds!

Right now, I have a nice assortment of prewound bobbins from Wonderfil/Deco Bob, Fil-Tec, Signature, and Superior (Masterpiece and Bottom Line).  Let me know if you’re looking for anything in particular!

The old-fashioned way

Wind your own!  It’s still a simple task and can be done with any sewing machine.  You might not be able to get as much thread on a bobbin as the manufacturer can, but you can exactly match your top thread with your bobbin thread.

Prewound or user-wound, bobbins are an essential part of machine sewing.  Know all your options, have courage and try new things!  Thread is half the fun of quilting!