Bobbins!

[BrendaP]

This looks useful:

https://www.sewingpartsonline.com/blog/understanding-bobbins-every-sewist-know/

Jessie

Interesting until she said the long bobbins are "for use in old Singer treadle machines".  It's nothing to do with whether or not a machine is powered by a treadle, by electric or by hand.  The long bobbins are for the old vibrating shuttle machines - and there are/were quite a few variations in size and brand!

[BrendaP]

Interesting stuff!  I still have to remember to call it a "bobbin" - my mum always referred to them as "shuttles" and therefore so did(do!) I.

Shuttles are the long narrow ones which go into a bullet shaped shuttle case,  found on older vintage machines.

[BrendaP]

I have four different types of class 66 bobbins.  Three of them are 'polished' or maybe chrome plated.  The darker one is less shiny and it is a little heavier than the others.  They came with my 1953 Aluminium 201K.  The others came with the 1940 201K and from Helen Howes.  They all work in both machines.

I think the holes are, as suggested in Jessie's video link, more for seeing how much thread is left on a bobbin, although when she showed the bobbin with concentric circles she said each circle represented a particular length of thread on the bobbin.  Poppycock!  If you use a fine thread any bobbin will hold more than if the same bobbin is wound with a thick thread.

I think there are two rules about bobbins.
1, Use the size designed to go into your machine.
2, If the machine came (new) with metal bobbins use metal bobbins and if it came with plastic bobbins use plastic bobbins. 

Also be wary of generic bobbins rather than those from the original manufacturer.  A while ago I bought some green plastic bobbins from Prym which are supposedly the same as the original blue plastic bobbins for my Husqvarna, but they aren't quite the same and I often get tension/stitch problems when I use them.

[rowe1311]

I might photograph my bobbins to see how many class 66 ones I have too.  Some of them don't work as well in the machine so will probably have to have sort through when I have a bit more time. 

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I have the last three types you list BrendaP. The one at the bottom is exactly like mine, but mine hasn't turned as dark. I have polished some of mine up, and it looks like either type can turn rusty or darker sometimes. Some of the brand new ones have a bluish shine to the metal, I'm wondering if they are chrome-steel, that would make the stainless.

There are a lot of advice on plastic and metal bobbins for new and older machines. I have an Elna with a plastic bottomed bobbin case, it takes metal bobbins. The sides of the bobbins are polished and rounded off, no sharp edges like on 15 bobbins. They are very much like class 66, and there are rarely any problem with Elna bobbin cases, metal or plastic bobbins. Singer had similar models, with plastic cases taking metal class 66 bobbins.

Later there has been advice on using plastic bobbins in plastic cases, but personally I haven't seen much problem with it. Some have reported damage to their machine. I have a few Apollo bobbins for my 201, and nothing troublesome has turned up when using them. I have cracked a couple of plastic bobbins during winding, but the winder was out of adjustment at the time.