Mexican made Nicholson files I tested are soft.

[george wilson]

Zach,the chipping teeth is from the hydrogen embrittlement which I mentioned that acid etching can induce. I think sand blasting would work better for rasps.

There is,though,a hard little skin on files,left by hardening with cyanide,which will be removed by any kind of sharpening.

The old books said that a good(there's the rub!)file was good for 40 hours of work. That was on steel,though. Thought I'd mention it,though this is a rasp thread.

[whit richardson]

All this talk about files beyond having some stock USA made files for standard shop duty what about this hand made files from France that PW keeps going on about? The Ariou and Liogier family firms are what I mean. If a tool is a dream to use, lasts for my sons to fight over and costs from $50 to $90 that's okay. I need some good quality rasps for fine curved work and my existing rasps are a bit coarse.

[george wilson]

There has been a long discussion about Liogier rasps,even with a video some weeks or a few months ago.