lawn mower steel for knife?

[LRB]

The maker who told you that is much mistaken. A file will cut, or at least scratch, anything softer than itself, within reason. It may not cut 64 Rc, but it should scratch 63 at least to the point that the scratch would have to be removed with an abrasive.

 

[Alan Molstad]

wont bite above RC 57 .

I just use an older file, one of them 1/2 round files.
I slide it off the top of the blade spine and listen to the sound.
Then I flip the blade and slide the file off the cutting edge, the sound should be different.

If the file snags the cutting edge, then I know I got trouble.
The file should really skate, almost as if the steel were a type of glass.

 

[J.Marsillo]

Thanks for clearing that up for me I do beleive the maker i was speaking with does a bit of hocus pocus when he makes a blade