Slate As A Natural Sharpener

Discussion in 'Edged Tools' started by ExAF1N1, May 24, 2012.

  1. ExAF1N1

    ExAF1N1 Purveyor of sharps and savory burnables. Supporter

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    Buddy of mine in his 60's told me slate makes a good "find your own" sharpening stone. Locally, our slate is loaded with garnet and layered. Not too hard to "carefully" bust some layers and get a flat surface at desired size whether pocket or benchtop. Anyone have some experience with "found" sharpening stones, especially slate? Have a couple cheapo knives I'm willing to sacrifice to experiment.

    Anyone who pipes in, please give some idea of your area so anyone from there can benefit. I'm in the Black Hills of South Dakota. Thanks in advance for your input!
     
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  2. harvey_birdman

    harvey_birdman Scout

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    I have never tried it, but I have thought the same thing. There is a lot of slate here in East Ky. So I am sure it would be good the know.
     
  3. Ironwood

    Ironwood Guide

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    I bet it would work. There's was a youtube video of a guy who said he could use any rock surface. He used a cinder block and got a great edge, so don't see why smooth slate wouldn't work.
    It seems that it is more technique of how you hold the edge to the surface, not so much the surface itself, as long as its flat, it should work. Stropping will help too.
     
  4. bigvisk

    bigvisk Scout

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    mygrandmother-in-law (old asian lady) sharpens all her knives on rocks. i dont know which kinds, but you on some you can see how her sharpening has left the rock smooth and with a curve. i dont know how sharp they are, but they are sharp enough for her. does seem to take her a while to do it, but she doesnt want my to sharpen them for her.
     
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  5. 556mp

    556mp Bushwhacker Vendor Bushclass I

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    I have used/use all the different sand stones around here in southern NY. they work well and you can find them in different hardness. They'll get a blade shaving sharp.
     
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  6. strongblackcoffee

    strongblackcoffee Scout Bushclass I

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    You can sharpen a knife with flint too.
     
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  7. Easy_rider75

    Easy_rider75 Bushwhacker

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    Interesting never thought of this. Buddy of mine is a slate roofer has tons of it over his house may need to swipe a couple chunks now
     
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  8. Galthoas

    Galthoas Tracker

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    I have used a chunk of granite to grind nicks out of blade before putting it to a chunk of fire brick to sharpen while in Kyrgyzstan deployed. It was a two part experiment one to see if it would work and two to see if I still had the skill to sharpen a blade enough to shave with. Ten minutes to take the nicks out, five to sharpen with the firebrick.
     
  9. jloden

    jloden Guide Bushclass I

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    Indeed, I was just popping in to say the same thing. Here's a couple pics from our last overnighter where Matt was showing Adahy and I how to find an use natural stones in various "grits" and use them for sharpening.

    Somewhere around here I have a couple stones I picked up on that trip, haven't gotten around to working with them yet but after seeing Matt wipe hair off his arm after honing his blade on a piece of quartz I'm confident the technique works :4:

    Here's Matt demoing one nice quartz stone that made for a great hone.

    [​IMG]



    Flattening a soft natural sandstone against another rock for use as a sharpening stone

    [​IMG]
     
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  10. Swede6.5x55

    Swede6.5x55 Guide

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    You can also use the ceramic bottom of your coffee mug as well.
     
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  11. JPAZ357

    JPAZ357 Scout

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    I learned this a couple years ago, and it's sure helped out in a pinch!
     
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  12. Medicine maker

    Medicine maker Guide

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    I really think this is a technique that needs to happen more and more should familiarize themselves with actually doing it. I enjoy diamond stones and ceramic rods but they simply werent around for most of time and require so much to make in modern life. No ones making them with no electricity. In particular one should look at @556mp and @jloden and I know there are others who also use this. And not just the damming attitude of you could sharpen a pry bar with a random stone. I mean seriously treating these stones the way they should be because there not just rocks they are whetstones. People need more proof this can be done and there are people here who can show it. These are the stones that sharpened swords and beheading axes. If nothing else people needed skinning sharp edged. Hell they needed shaving sharp edges. All without diamonds, ceramic or even specifically for oil stones. They did it all with their local river and the stones it offered. Hell Japan has the best stone in the world for katanas and im pretty sure they dont dam natural rocks for sharpening.

    I barely feel right using my ka-bar oil stone from 1890. Ive just begun my journey of freeing myself from the modern sharpening stone. I have a few random flat river rocks. And while I couldnt get the edge I would have liked, I did get more edge and I avoided causing damage. I hope there is some spread of this technique and mindset and if anyone has any tips or anything more they can show id really appreciate it. Even just some positivity to this technique.
     
    Last edited: Feb 15, 2019 at 10:14 AM
  13. BCWoodsman

    BCWoodsman Wet Woodsman Supporter

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    We don't have slate around here, but we have a type of shale that I have used to put an edge on my old Winchester Hunter. It works well. It is a tough form of shale that also yields excellent cutting flakes - super sharp and quite durable. On one camping trip I had 3 tires on my truck shredded by the shale and had to have a conservation officer help me get some replacements from town.

    I have also used random smooth river rocks for good results.

    I am on the southwest coast of BC.
     
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  14. tristndad

    tristndad Supporter Supporter

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    I can see slate as a way to hone your edge, however I can't see it being a means to sharpening a blade. Slate is much softer then steel and would not remove the material from the steel needed to be considered sharpening.

    This is my opinion only, I have no first hand experience. I do, however have plenty of experience both with working and playing with slate, and sharpening many knives.
     
  15. Barry J

    Barry J Scout

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    I saw a video of a guy splitting a stick, then ground a flat surface with a rock. He rubbed the flat surface with charcoal from the fire. He then stropped his knife on this surface. I have been wanting to try this.
    I have also heard that river stones can be ground against each other to form a flat surface, and then used to sharpen a knife.
    I have never seen anyone use slate or shale as a sharpening stone. Sure is worth a try!
     
  16. batmanacw

    batmanacw Guide

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    This works very well.
     
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  17. bigfoots

    bigfoots Scout

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    Just find a couple of pieces of slate wet them and rub them together to smooth them out a bit and it works great. I've sharpened several knives with this piece. IMG_20190213_173411.jpg
     
  18. Kyle363

    Kyle363 Supporter Supporter

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    You can use the back of ceramic tile. Pretty much any flat abrasive surface can be used.

    I don’t have slate near me but pretty much any finely grained stone can work. Now this is all dependent on the steel and how much work needs to be done. I wouldn’t try to sharpen any crazy hard wear resistant steel this way but more basic carbon steels and tools steel will work.

    The way I’ve done it is you walk around and pick up stones that are already semi flat and in the size that works for you. If you can see the grain size you want something pretty fine. You’ll need two stones. Knock the two potential stones together and listen to the sound the higher the pictch the better the stone is for sharpening. Once you’ve selected which stone to use you then need to flatten it on another stone. Use water for this process. Once flat sharpen away.
     
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  19. leghog

    leghog Scout

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    And the frosted edges of your car's roll down windows.
     
  20. 556mp

    556mp Bushwhacker Vendor Bushclass I

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    Last edited: Feb 13, 2019 at 6:45 PM
  21. RTDoug

    RTDoug Scout

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    If I remember my geology, slate is formed from shale.
    Whatever you find that can re-align your carbides... good enough!
     
  22. OrienM

    OrienM Guide

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    I've been experimenting with river-rock sharpening, and can now get pretty good results using select smooth rocks...often quartzite, basalt, or chert/chalcedony. I even sharpened my machete on a red clay brick a couple weeks ago, and that worked pretty well also....nice and flat, lol.

    Natural-rock sharpening works better for me using a backwards (like stropping) or lengthwise stroke, rather than edge-first. I can't quite get 'hair-popping' sharp yet, as I can with oilstones and strops, but I'm working on it.
     
  23. A Seedy Lot

    A Seedy Lot Scout

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    My son has been using limestone based rocks he pulls out of a river to sharpen his A2 knife.
     
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  24. DavidJAFO

    DavidJAFO Supporter Supporter

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    hello,
    @ExAF1N1 https://bushcraftusa.com/forum/threads/suggestions-on-sharpening-stones.213788/#post-3648490 I first used a slate whetstone strop in my teens (a long time ago). The types of Welsh slate I mentioned (quarried) Dragons Tongue & Purple Llyn Melynllyn the Green/Grey colour. I asked my Welsh friend way back from Senghenydd (South Wales) about such, this is nicknamed "Welsh Thuringian" aka Cambrian Green. These slates are difficult to gauge the grit, as the slate is so smooth. In wetting the stone by either oil, water or *spit (saliva) the slate produces a surface slurry or film which acts like a paste this hones the blade in no time. I'd put the Welsh slate up against the other types of Whetstone any day, they're an excellent alternative to branded commercially bought whetstones. :)
    Regards
    David
     
    Last edited: Feb 14, 2019 at 10:53 AM
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  25. Medicine maker

    Medicine maker Guide

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    I’m am talking about stones in general as much as slate.
     
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  26. Jim L.

    Jim L. Guide

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    Oh. My. Goodness.

    Genius. This may warrant a trip to the Home Despot.
     
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  27. TAHAWK

    TAHAWK Guide

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    I have used shale, limestone, and sandstone. Lots of it around here, esp. in road cuts and on the Lake Erie shore. I keep the best pieces and use them routinely. Except for the uber abrasion-resistant steels they seem to work fast enough for me and produce a fine edge. Grandma used the edge of her pickling crock to keep her knives wicked sharp.
     

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