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Thinning a Blade

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  • #16
    I have a couple Oscar Ukrainian gouges made by Stryi Tools. They are hardened using liquid nitrogen which turns the steel into martensite. Now I’m talking about this like I know what that means. Really I’ve just read about it online. What I do know is those gouges hold an edge as well if not better then my Pfeil Swiss Made tools.
    Living in a pile of chips.


    • #17
      Martensite is a type of steel with a distinctive atomic structure. Though martensite is very hard, it is somewhat brittle, which.. Tempering

      The resulting martensitic steel is extremely hard, meaning that it won't scratch, but very brittle, so it will break under stress. To address this weakness, martensite is heated in a process called tempering, which causes the martensite to transform partially into ferrite and cementite. This tempered steel is not quite as hard, but becomes tougher (less likely to break) and more malleable, and thus better suited for industrial use
      . . .JoeB


      • #18
        I have modified stainless blades by hand with a file. Slow, but quiet and control is good. Burning the steel won't happen. You don't end up breathing anything in either. Nicholson file less than $10 and you might find them at Walmart.
        Last edited by Buffalo Bif; 10-21-2019, 03:56 PM.
        Buffalo Bif


        • #19
          I ended up going the route of 120 grit wet/dry sandpaper. (Actually had to go to an auto parts store to find it locally.) It took a very long time, and I wasn't really able to get the thinning I wanted, but I was able to at least make the bevel shallower, thus putting less metal in the wood at a given depth. No projects on the board at the moment, but the few practice cuts I did seemed to go better without splitting the wood grain. So here's hoping.

          Thanks for all of the input.


          • #20
            Keep at it TennsDog. I would work at a tool for a bit and then put it down when I got tired. Wait a few days then I would go back at it. If I keep at it for too long, I'm liable to make a mistake. And as I went along, the practice cuts would improve, telling me I was on the right track.

            Bob L


            • #21
              That is why I start with a corser grit, to know down the metal a little fast, the go to the fine grids
              . . .JoeB


              • #22
                It's a matter of experiment to figure out, for your steel, which grit to start with for the rough work.
                I've accumulated everything from 60 grit up to 2500 grit papers.

                Some really hard steels need more work with finer grits.
                But to stop just short of overheating the steel and cooking the blade.
                The steels in farrier's crooked hoof-trimming knives can be really different.

                Mora(Frosst) from Sweden is some sort of stainless steel. Not too hard but holds an edge OK.
                Hall (Canada) is very much harder. I wreck a new chainsaw file just trying to scrub down 2 blades.
                I used to try to start with 80 grit but gave it up as a waste of time.
                So next I tried a chainsaw file and that seems to be the place to begin.

                I'd be quite willing to guess that blade steels vary just as much in different kinds of flat knives.
                Just putz around with it from time to time and see what you can make of it.
                I'd also be looking around for other steel blades that might be OK to start with.
                The guys in the rustic furniture shop down my street like to start with worn out Sawz-All reciprocating saw blades.
                Brian T


                • #23
                  I don't know the size of the blade you are working, but maybe this chart will help you.
                  Claude Knife blade thickness.jpg
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                  • #24
                    Thanks, Claude, printed & filed for future reference, Boy some of the knives really have a small included angle, makes sense for detail knives Thumbs Up
                    . . .JoeB


                    • #25

                      Thanks for the chart, Claude.
                      Think of that included angle as a wedge.
                      A wedge that you jam into the wood and try to push it open.
                      Very shallow cuts (detail) are the easiest.
                      But that also means that the edge is prone to crumple and get folded over because it's so thin.
                      Cut in a slicing motion skews the blade so the apparent angle is even less.
                      Never even dream of prying out a chip.
                      Brian T


                      • #26
                        Great reference material Claude. Thanks a bunch for sharing. Always wondered about comparisons to a Goodman knife. Now I know.