Dimensions Guide

Bobbin sizes differ so as to meet the needs of different users. By far, the most common bobbin dimensions are L Class, Class 15 and M Class.

Bobbin Types: a Comparison

A lot of sewing machines use one (sometimes two) of these bobbin classes. However, it must be stressed that they are not interchangeable. A sewing machine designed for M Class bobbins won’t be able to use L Class types.

The M Class is 1” and the L Class is ¾” in diameter. The M Class is larger than the L Class, so it can’t be used. The L Class can be fitted on the M Class, but you can’t sew on it. Since the bobbin size is not correct, it won’t fit in. The bobbin would slide and lead to complications.

Given the size disparity, it’s obvious the M bobbin packs in more thread than the L bobbin. The M Class bobbins are employed in industrial machines. They are also utilized in longarm machines.

L Class and 15 Class Bobbins

The L Class and 15 Class bobbins are the ones used in home sewing machines. The embroidery machines fitted with a vertical rotary hook bobbin rely on the L Class bobbin. These machines cannot use the Class 15. A lot of the major manufacturers (like Babylock and Brother) use bobbin size Class 15.

Although L Class and Class 15 are thought to be interchangeable, they are not. A regular L Class is 5/16” high and ¾” wide. The Class 15 is also ¾” wide but 3/8” high.

The difference is in the height. Because they have similar widths, the assumption is one can be substituted for the other. However, this isn’t as easy as it seems. Check the manual that came with the sewing machine. You’ll see that you must wind the bobbins using particular threads for the Class 15 bobbin. The reason is that the machine is designed for specific bobbin sizes.

A lot of users also don’t want to wind the bobbins. In terms of convenience, pre-wound bobbins are more logical. A lot of pre-wound bobbins are in the L Class. Due to the fact, machine makers add a center pin to make up for the disparity in height.

What to Use

The best way to learn is by trying them both. Try to get your hands on the three sizes mentioned and use them. Run as many tests as possible to help you determine which best suits your needs. Not only are the sizes different, but so are the brands. You can try different tones or you can get recommendations from friends.

Other Applications

The bobbin can also be used on electrical equipment. When utilized in electric components, wires are wound on the bobbin. The wires are packed with magnetic properties. For bobbin lacemaking, several types of bobbins are used, often made of different materials.

Choosing the right bobbin size is not difficult. Since there are only three sizes, picking the right one will be easy once their properties are understood.

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