[elevation]

I haven't read Postrel, but the idea of twine being necessary to secure a stone tool to a wooden shaft seems wrong to me.

Jon Plant secures a stone tool head to a shaft by building a stone axe called a "celt" with more primitive methods [0]. The friction fit he achieves is likely more robust than a twine lashing because it helps deliver a higher impulse to the work-piece than a mount made of cordage.

[0]: https://www.youtube.com/watch?v=BN-34JfUrHY