None of my machines are particular. I use either plastic or metal, depending on which I grab. I have two vintage singers, one a treadle using a class 15 and one an electric using a class 66. I use plastic or metal on my dinky mechanical Brother which is the least fussy machine I have ever owned. It doesn't care about bobbins, threads or needles and will sew anything. (I feel like I bragged on it too much and now when I go to use it it will crash on me!!!!!!!) Of course the featherweight uses it's own bobbin, and I only have metal ones. Maybe that's all that's made for it.