So I started a test world with no mods and gave myself 3 fab, 3 mechanic, 3 tailoring, and 3 survival, debugged in a soldering iron, welder and makeshift welder. If I go to reinforce my boots , each tool gives a different % damage. Is why I said that.
Edit: ah you said success, well I could have sworn i my current run the success chance was different depending on whether I used the welder or soldering iron, does one use fab and one mechanics and that is why?