Bobbin types links to learn more

Bobbins are NOT interchangeable between all sewing machines, there are MANY different sizes and styles or classes of bobbins, and bobbin cases, so it is important to learn which type your sewing machine uses, and make sure not to accidentally mix them up, if you have machines with different types of bobbin systems. As more machines are made, new sizes and styles of bobbins and bobbin cases are being created, so no information about bobbins, will have EVERY single type of bobbin system ever made, unfortunately.

The majority of vintage home sewing machines, especially those manufactured in Japan, use the class 15 bobbin system, originally used on the Singer 15, which is what the Japanese models were originally based upon.

Singer sewing machines use various sizes of Vibrating Shuttles (Singer 27, 28, 127, 128, and the other early long bobbin Singer sewing machines), but others use the class 15 bobbin, others use the Singer class 66 bobbins, with the look of a metal doughnut. Singer also made special bobbins for their many different Touch & Sew line of sewing machines, which are plastic, and are not interchangeable between many models. 

Singer 127VS 27VS long shuttles in their PuzzleBox case

Singer 221, 222, and 301 all use the same rare type of tall flat bobbins, and the special Singer bobbin case (the new replacement bobbins and bobbin cases made in China are apparently problematic) though some industrial sewing machines apparently use the same type of bobbin and bobbin case, though I have not tried to interchange them between the two, to be sure if the industrial bobbins fit the home models.

Sewing Parts Online, has an excellent pictorial tutorial here-

SEWING PARTS ONLINE BOBBIN INFORMATION

Kenmore sewing machines came with various bobbins, as well, with early models being long shuttles, then White bobbins, but the Soryu and Maruzen manufactured models mostly use the standard class 15 bobbins, regardless of whether they have 7 holes, or 9 holes, or have solid sides. 

Necchi class 15 bobbins seem to be the same as regular class 15 bobbins, I actually have original Italian Necchi aluminum bobbins for my Supernova, and included some in the Necchi BU I traded for some homemade Christmas teddy bears.

Vintage Bernina home sewing machines use a proprietary bobbin which looks like a class 15 bobbin and bobbin case, but you will find the Bernina sewing machines actually sew noisier, and with more stitching problems, if you use a standard class 15 bobbin case, or bobbins. There is what appears to me, to be a 1 mm variation in the height size, which is why you really should use the Bernina bobbin cases and bobbins, if you really want the quiet, smooth Bernina sewing, without problems.  You get skipped