Never used them, will not put them in my machine!

I only use the bobbins that are recommended for my machines. Right now none of my machines use plastic bobbins.

If bobbins are interchangeable why can't you wind different bobbin on a particular machine. I have three Janomes and one Bernina and I can use one machine to wind bobbins that I use in another machine.

My machine takes the plastic ones. I do not know if it can use the other. I have not had any break on me. Wonder if your machine needs the metal ones. What does the owners manual say?

:) yes, I agree but my Singer from 1990's came with plastic ones so that is what I use -- I have learned to look at the bobbin to make sure the top thingy is straight and not bent before refilling it -- more of planned obsolescence

I agree, it just doesn't seem that something plastic would work in such an important part of the sewing machine. Bernina doesn't offer them so I have never used them and I wouldn't have even if they offered them.

Why couldn't you. Sometimes people buy prewound bobbins and it is for sure they don't know what machine wound those...

I wind most of my bobbins on my Janome 350E as it winds the BEST bobbins! Tight, reasonably fast and there is no place for lint to gather that I can't get to as it is on the top of the machine. I can see the whole thing. I have three Janomes and use the same bobbins in all of them. Both plastic and metal.

Bobbins aren't interchangeable unless they're the same bobbin size. Bobbins are manufactured to specifications, and sometimes the differences in specifications are hard to see with the naked eye; the hole could be slightly smaller, or some other dimension different by just a couple of centimeters.

Makes a difference to the machine, though. I once "fixed" a machine that was brought to me because it jammed when it sewed. Owner said it worked fine until she ran out of thread and inserted a new (plastic) bobbin. Turned out the new bobbin was not quite the same as the old bobbin, even though they looked very similar. When I looked closely, I could see that one had slightly curved edges while the other was straight.

I have some metal bobbins and some plastic. I much prefer the metal ons.

However, i do use the plastic ones for a specific purpose. I always use my "good" thread for piecing and quilting. I always put my "good" thread on metal bobbins. That way I know it it the good stuff!

I have a bunch of older, cheaper thread that I use for mending, basting, or making something that I know is not going to be expected to last a lifetime. I put that thread on the plastic bobbins. That way, I know it is the less than great quality thread! Works for me!

I use plastic as metal will wear out plastic casings also if you have a thread sensor it also needs to be able to sense when thread is getting low so it needs a clear bobbing, its why paper prewounds don't work with sensors. I haven't had any problems with my bobbins breaking unless i accidentally step on one. But I also bought a package of like 50 for 5 bucks so I have plenty and am not constantly using the same one