Question about bobbins and bobbin cases
 

If a machine uses a Class 15 Bobbin - do all the machines that use a given style/size of bobbin use the same "model/style" of bobbin case?

Or a Class 66 Bobbin - or whatever?

Just wondering.

I think the bobbin cases are different. 15's are taller than 66's.

Yes-and no. A 15 class machine will use a 15 class bobbin case. Straight stitch machines will use one that has either an 11 o'clock finger(points to the left from the top) or a 1 o'clock finger(points to the right). Most are 1 o'clock. From there you have one more difference. A front loading zigzag machine needs a bobbin case with a longer slot on the top of it. A straight stitch machine or an end loading machine(both straight stitch and zigzag) can use a short slot bobbin case.
L style rotary bobbin cases don't have a finger, they look like an industrial bobbin case. At least my Pacesetters' bobbin case does.
Class 66 bobbins are horizontal, they drop into the machine so no removing the case to change a bobbin.

Cari

To put it more simply, most machine models have their specific case, while the bobbin is usually of a more general standard, like class 15 or 66. I don't think very early Singer model 15 had the little finger pointing either 11 or 1 o'clock. There were some develoments in the bobbin and hook area in the early years. Neither model 99, 66 or 201 have the same bobbin case, all take class 66 bobbins.

Thank you -

A sort of easy way to figure it for a Singer, if it drops in it is more likely a 66 if it goes in a pull out case it is more likely a 15 but there are other bobbin types, too. There are lots of different bobbin cases that take 15 bobbins. If you look for bobbin cases and bobbins for sale you will see a good variety of types.