I used my Tenacious to practice adding a sharpening choil. It is functional but came out kind of ugly. Then I used it to practice free hand sharpening.
Spyderco: Tenacious, DLT Manix 2 (Red G10), MT27
ZT: 0566FDEBW, 0562CF, 0450CF, 0357BW
Kershaw: Link 1776GRYBW
Boker: Massdrop Blue Urban Trapper
Leatherman: PST, Charge Ti