I just came up with a simple design for a scraper that works well and just about anyone should be able to make if they want to try and get fibers from leaves. Such as yucca, agave, flax, cabbage palm, palmetto, etc.

https://youtu.be/bT9yY5dE5rE

Turn on closed captions for more info in the video. I did closed captions so automatic translation should work too.

Yeah...I dunno. Too sharp is bad. I tried the cutting end of a wood chisel...too sharp. The 90° edge of the chisel was fine though...that gave me the idea for this.

You mean a wood scraper for bows?  Maybe.

Ah, yes.  I think the only issue is that you need to put a lot of downward pressure, and it is hard to hold on to something that thin and not bend it, but it could work, certainly.