- I use a variety of metals depending on the qualities desired of the blade. The most important thing is that I only use metals from trusted sources. That is, I never use "mystery steel". "Mystery steel" is any steel from a questionable source. Leaf springs, saw blades, etc.... while these metals have the potential to make quality blades no one who uses these metals can actually tell you what metal they are using... as such there is no way for them to be absolutely certain that their heat treat processes are creating consistent results. Here at Last Resort Blade, unless you specifically ask me for a knife made from your grandfather's farrier rasp (and we have had a discussion about the potential pitfalls of mystery steel), your knife will be made from 1st quality custom milled steel... Let me know the intended use for your blade and I will recommend a few steels that meet your needs.