Chances are, there will be a few stringed instruments. I would suggest that there be a number of ways to make string for stringed instruments, which would make them modular.
Either, stringed instruments can just take an amount of 'string' as currently exists using the Simple Twiner, or the twiner should have new projects added for 'instrumental strings' for silk, cotton, and possibly hemp.
As for the violin - what's going on there? The resources are very primitve, but the tools are pretty specialised - either make the resources and tools both primitive, or up the resource requirement to string.
As for possible stringed instruments (all of which should take the same tools as the violin, pretty much):
A Zither
A fairly generic term for anything from a Kanun, to various Greek varieties, and varieties from further east, such as the Chinese Guqin and Japanese Koto.
Guitar, Bouzouki and Sitar
All fairly similar, requiring wood and string to make, although the guitar should maybe need a small amount of steel or iron.
Harp & Gilted Harp
Requiring wood, string and a small amount of steel/iron/bronze - the gilted harp should require a harp, and an adequate amount of gold and a hammer.
Lyre
As harp, but smaller and no metal
Kora
Wood & sinew or string
I think names should be kept neutral, and generic as possible - but be aware that most 'generic' terms are western in origin - a guitar covers a possible range of instruments - lute, even the Greek Bouzouki, but doesn't adequately cover the sitar or Kora - same goes with the zither, the Guqin and Koto are quite different from western versions.
