I have a threader that came with my 201K, it's numbered Simanco 121632. I've seen a few different vintage Singer threaders, but so far nothing that fits on the needle bar. They are quite a lot of them on fleabay and the web in general. I think most of the brands had some type of hand held device to make it easier. My best trick is lots of light, a pair of sharp scissors near by to snap of the end of the thread, and a visit to the optician when it get too bad.