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Sharpening Pressure

Discussion in 'Maintenance, Tinkering & Embellishment' started by MtnHawk1, Jun 29, 2019.

  1. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    Agreed ^ . I rebeveled a 9" slicer of 440C steel on a 'new' X coarse Dia- DMT plate. To me I wasn't exerting a lot of pressure during this rebevel but the swarf showed it was a lot. The diamonds just sheered off and piled up. So, it does indeed occur. Now I don't dare rebevel on a diamond stone. Instead I'll use a SiC stone as they have much more material to cut the steel. Then use the diamond to finish up on. Plus, the diamond cut no faster. If I had used light pressure the process would have been slower using the diamond and I may have saved some grit. Lesson learned. DM
     
    MtnHawk1 likes this.
  2. Diemaker

    Diemaker KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    427
    Apr 28, 2017
    Too many variables to say one abrasive is faster than another. Both the bond and steel being cut will have a huge inpact on which abrasive is best. One question is how much stone wear are you willing to accept for a higher rate of metal removal? Bearing down on a corse Sic stone tends to make them disapear fast. No free lunches here. If you don't want your stone to wear as fast you have to lighten up the pressure. In my experience diamond is the sharpest abrasive I have used to make stones out of, hands down. Granted I have not tried CBN, because it's 10x the price of diamond, but it is my understanding that it is not quite as sharp. Because diamond is so sharp it will dig into the steel with less pressure, which may lead to crystal fracture, with low quality diamonds, or much more likely pulling out of the bond. You may be able to remove steel faster using more pressure with a Sic stone but you are also removing a lot more stone that way too. Everything is a compromise, with good diamond stones used properly they don't need to break down to stay sharp so they can work with virtually no wear.

    I really don't think work hardening the steel is something you have to worry about with hand sharpening. If this is an issue then diamond is by far the best abrasive since it is so sharp and cuts cleaner than any? other abrasive. What you should worry about is flexing the apex with dull abrasives, that can affect it far more. That fine bit of steel hanging out in the air is very flexible, which is another good reason to use light pressure and the sharpest abrasives so you flex it less while sharpening.

    What is work hardening? Copper work hardens quite well if you want to see it for yourself. Take a copper wire and bend it back and forth slowly holding it far from the bend. After 2 or 3 bends it will no longer want to bend in the same place, it will bend next to the original bend since the wire has become harder from the "work" of bending it.

    When trying to flatten a large surface, like plane blades, with another large surface, the stone, then lapping with loose abrasive on a flat surface will work worlds better than a stone. This is what you are doing when you work up a slurry on your stone, the slurry is the loose abrasive and the stone is the flat plate.

    Keep in mind I don't think there are any really good brazed diamond stones available for knife sharpening. By good I mean vacuum brazed with a nickle/reactive metal bond. I make a lot of my own diamond tools to cut stone and quartz, as in I make the steel bodies and send them off to have the diamond applied to them. Some of my tools are vacuum brazed. When this bond is done correctly the diamonds will not pull out, even with 75% of the crystal sticking out of the bond. Yes Virginia, the bond makes all of the difference. The last sentance can not be overstated.

    I am a big proponent of edge trailing passes with diamond stones once your reach the apex. The reason is I see much less damage to the apex when using edge trailing passes vs edge leading under the microscope. Also I NEVER would even entertain the idea of doing an edge leading pass to remove the burr. This will fold the burr onto the bevel damaging both the apex and bevel, the last thing you want to do to finish sharpening your knife. Deburring the apex is exactly what I think a strop is for, for most steels bare leather is my choice.

    I have never disclosed what resin I use on the Matrix stones. I know Mike Emler has called it epoxy but he uses this as a general term for plastics.

    The the Op, have a look at the Baryonyx Mutt stone for your coarse field stone. I think that may be what you are looking for.
     
    MtnHawk1 likes this.
  3. DaveDM

    DaveDM

    46
    Dec 21, 2017
    Any plans to offer plated diamond stones !;)
     
  4. Diemaker

    Diemaker KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    427
    Apr 28, 2017
    No, because I think resin bond is the better compromise for knife sharpening. They may not hold the diamond crystals as well but when those crystals get a little dull you can dress them back to new condition, many many times. The bodies would have to be steel, or better yet a 400 series stainless steel, my cost to have the diamond applied would be the same or more than the retail price of my own resin bond bench stones and they are only good to 400 grit, beyond that you get the occasional proud crystal.
     
    DaveDM likes this.
  5. eKretz

    eKretz

    930
    Aug 30, 2009
    Pretty self explanatory. A wide bevel is a bevel that has a relatively large amount of surface area in contact at once. A very high surface area item would be something like a plane blade back. And yes, diamonds dull. This surprises you? Everything wears when exposed to friction. Even diamonds.
     
  6. Twindog

    Twindog Gold Member Gold Member

    Apr 6, 2004
    How do you dress diamond plates to bring the diamonds back to snuff?
     
  7. sickpuppy1

    sickpuppy1 Basic Member Basic Member

    408
    Sep 27, 2018
    Let’s see if this works.
     
  8. eKretz

    eKretz

    930
    Aug 30, 2009
    Yeah you don't bring the diamonds back to snuff as in sharpening them. You use a loose grit abrasive to gouge and abrade the binder away so that dull diamonds are dislodged and fresh ones are exposed.
     
  9. Diemaker

    Diemaker KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    427
    Apr 28, 2017
    Yes you wear away some binder to expose fresh diamond. Normally the stones slow down cutting and I think it's because the exposed diamonds get pulled out so you need to reveal the ones left enough to cut. With this in mind you only need to remove enough binder to expose around 20% of the diamond crystals, say just over the scratch depth you want. With a 650 grit stone that means you would need to remove about .0002756" of binder, with a 4k stone it would be .0000314", either way it isn't much. IF you don't overdo the dressing they will last a really long time. I find the 80 and 250 Matrix stones don't need maintenance dressing if you keep the pressure light enough, which is still some pressure, the swarf will wear the binder some so keep it cleaned up. The 4k I need to dress every 30? 3" knives I sharpen, I'm at 25 knives with my test set and they still look and work fine. With my abuser set I might dress the 2300 and 4k stones every 15 knives or so and the 1100 then 650 much less.
     
  10. MtnHawk1

    MtnHawk1 Gold Member Gold Member

    129
    May 22, 2019
    Exactly! It has taken me many months of sharpening, trial and error, and research to arrive at this simple conclusion, and I appreciate you confirming it! :) Trying to figure out all these variables and get the best stones for what I need has taken a lot of enjoyment out of maintaining my knives, as well as taken too much money out of my pocket. I don't have the time or interest to spend a lot of time sharpening, so like to do it as quickly as possible, but I respect my knives for the quality tools that they are and want to maintain them as well as possible. Fortunately I am happy with good utility, toothy edges and don't need highly refined and polished knife edges, so that saves some time and energy. I am just going to keep it as simple as possible from now on, without trying to achieve sharpening perfection, and get back to enjoying what I do.

    Regarding your question about sharpening pressure and stone wear, my time is more important than a relatively inexpensive stone, so I don't care much about minimizing stone wear. I would think that a certain amount of abrasive has to be removed to remove a certain amount of metal, and that it wouldn't matter if the abrasive is removed fast or slow, but that is just an intuitive guess.

    Thank you for this! I read about the advantages of edge trailing passes once in awhile but have never heard the rationale behind it. I appreciate the bare leather tip, too. I've wondered about that for a long time.

    Coincidentally, some Manticore stones from Baryonyx arrived yesterday, the same day as your post! Thanks for your recommendation of the company's stones (their customer service has been great!). I hope the Manticore will hog off metal as fast as the Mutt.

    Thank you for your very informative post! :thumbsup:
     
  11. sickpuppy1

    sickpuppy1 Basic Member Basic Member

    408
    Sep 27, 2018
    Mtnhawk, one thing I will recommend. hopping you watch at least some of the video. you mentioned that you dont care too much about minimizing stone wear, but part of the reason the dressing the stone is done is to make sure the stone are flat also. So they may need to be done at some point to flatten the stones from normal wear. Sharpening could be a pain in the butt if you stones got wallowed out in the middle or edges. Just something to keep in mind down the road.It would probably take quite a few knives b4 it became an issue anyways.
     
  12. MtnHawk1

    MtnHawk1 Gold Member Gold Member

    129
    May 22, 2019
    sickpuppy1, thanks for your post and good point about stone wear and flattening.

    When I wrote that I don't care much about minimizing stone wear I was thinking about 60 grit stones. Since they are used to just hog off metal I don't think flatness is as important as higher grits used for a more refined edge. I should have been clear about that.

    Wowbagger, my posts were not about damaging my knife edges, but about potentially damaging diamond sharpeners by using too much pressure. The instructions say to use light pressure only.

    At first I did not understand why you did not damage your 220 grit diamond plate with so much pressure but, from your explanation and others, I now see that using higher pressure with diamond stones is ok if it's spread over a large enough area. This is very good info to know and I appreciate you pointing it out! :)

    Did you go to the apex with the 36 grit? I've seen warnings not to apex with very low grits because of edge damage.

    eKretz, thank you for your detailed explanation. That was very helpful. :thumbsup: I wish I had learned this many months ago but the instructions with the diamond plates I bought said to use light pressure, so that's what I did.

    DeadBoxHero, thanks for your good advice about setting the shoulder and making and removing burrs. I especially appreciate your info about vitrified diamond/CBN being able to take more pressure than diamonds. I didn't know that and will definitely consider CBN in the future. It looks like at least some CBN stones can be used dry. I don't like using lubricants, especially oil, which is a major reason I started using diamond sharpeners.

    kwselke, I agree with you that light pressure is essential for tasks such as finishing an apex, microbevelling, removing burrs, and steeling, but when it comes down to things like thinning a thick knife edge, heavy pressure with a coarse stone removes metal much faster than light pressure, in my experience.
     
    eKretz likes this.
  13. MtnHawk1

    MtnHawk1 Gold Member Gold Member

    129
    May 22, 2019
    This is very relevant and interesting! Many years ago, when I was starting to learn freehand knife sharpening, I bought a DMT XXC and, not knowing better, probably used too much pressure to relief grind a thick SR101 knife, although it was over a large area. From what I read from research, and on the forums at the time, I thought excess metal would jump off the knife and run away at the sight of this diamond plate, so was disappointed that I didn't get the quick results I thought I would, and probably ruined an expensive stone. Since I was a newbie I figured I probably did something wrong.

    This wasn't true just for diamonds. I've been disappointed with (around) 120 grit stones in general for not hogging off metal as quickly as I thought they would. I purchased a Baryonyx Manticore 60 grit stone recently. I've only had the time to use it once briefly but, from what I saw, I am optimistic that this is what I've been looking for.

    A couple of questions, if you would:

    What are "vitreous" stones?

    What does "recondition" mean in the sense you are using it? I usually use silicon carbide stones without lubrication, even though this goes against common practice. Do silicon carbide and aluminum oxide stones need to be reconditioned or is this only for other types of stones? If they do, I'd appreciate you explaining how to do it.

    Thank you!
     
  14. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    He should write today... DM
     
  15. HeavyHanded

    HeavyHanded

    Jun 4, 2010
    Vitreous means the stones are fired with glass or some other material as a binder. Regular combo bench stones and India stones.

    If you really lean on them you wear the abrasives down faster than thet can tear out and refresh the surface. They glaze and then because they have nowhere for the spent abrasive and metal shavings to go they plug as well.

    Best way to recondition them is with loose grit SiC, 30-60 grit or so and a very hard backing plate or stone to lap it against. Enough water or oil should be used to make a paste.

    This makes a big difference in how well a coarse stone can cut. Most coarse stones are a disappointment.
     
    MtnHawk1 likes this.
  16. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    I like the way the ACE Hardware SiC stone cuts. When I apply a layer of Vasoline on it the mud generated stays. When I just use oil the oil soaks in quick and little mud remains. Cleaning this stone with plenty of oil and a bristle brush does a good job. Then wipe with a cloth. It sheds grit and cuts well. It is more coarse than the JUM-3. DM
     
  17. MtnHawk1

    MtnHawk1 Gold Member Gold Member

    129
    May 22, 2019
    I've given up trying to freehand relief grind with stones or diamonds in the 100-140 grit range, no matter how their grit size is labelled (extra coarse, coarse, or whatever). Once I have removed the most metal that I'll ever remove (by relief grinding) then if I want I can use stones in this range for sharpening.

    I've been gravitating towards silicon carbide more than diamond so I can use more pressure. I also like toothy edges, so the Norton Crystolon Combination in coarse and fine would be perfect. I think the coarse is 120 grit and the fine 320. I don't need refined and polished knife edges.

    I first read about not using lubricants in John Juranitch's book, The Razor Edge Book of Sharpening. Probably few in here agree with that but I don't have the time or interest to relief grind or sharpen any longer than I have to. Using no oil or water is faster and less messy. Also, I sometimes sharpen my knives in the wilderness, and only carry a minimal amount of sharpening supplies to help minimize the weight I carry. Using lubricants here is even more of a hassle than at home.

    This is exactly what I've found! Thanks for this. It's reassuring to get confirmation of my results from those who are more knowledgeable and experienced about sharpening than I am.

    I've also read good things from others about an Ace Hardware stone that is coarser than the 120 grit Crystolon but the only ones I could find on their website is a 60/80 grit. Is that the one you are referring to?

    Yes, this is what took me a long time to find out, at least for what I want to do with them and what I expected them to do.

    Thank you for answering my questions!

    I keep seeing references to your online videos, but can't find any. If they are still there would you please give me a link?
     
    Last edited: Jul 18, 2019
  18. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    No. The stone is a ACE Hardware exclusive. It is supplied by Norton to the ACE system warehouse. It is a 2"X 8" stone, the coarse side is more black (90-100 grit) and the fine side a medium is dark grey (220 grit). I just kept watching at stores until I found one.
    Employees don't know the difference. The sku number is 21165 and 21160 for the 2" X 6". I use this stone with oil to relief grind. I would do it at home. It only takes 10 mins. or so. I've done it on a few of my knives with thick convex grinds. It makes a big difference. I wouldn't carry these stones backpacking. I've hidden a stone off the trail in an area that I like returning to. A year later I have found it and used it. It's not like they rust. When hiking you want something that will bring an edge back to a usable sharpness. Good luck, DM
     
    MtnHawk1 likes this.
  19. bucketstove

    bucketstove

    Sep 23, 2014
    Hi,
    How sure are you its supplied by Norton?
    I thought it was ali/gator, Internet seems to back it up
    http://gatorfinishing.com/products/hand-sanding/misc.-tools----hand-sanding/sharpening-stones
    Available Sizes: 4",6",3",8",10"
    Available Grain: Aluminum Oxide,Silicon Carbide
    Available Grades: Coarse/Medium
    Item No. Grade Grit Pk. Qty. Inner/Master
    6050 3” Pocket Stone - 1 10/50
    6063 4” x 1-3/4” x 5/8” Combination Stone 60/80 1 -/10
    6047 6” Grinding Wheel Dress Stick 20/24 1 -/10
    6061 6” x 2” x 3/4” Combination Stone 60/80 1 -/10
    6060 6” x 2” x 1” Combination Stone 60/80 1 -/10
    6058 8” x 2” x 1” Combination Stone 120 1 -/10
    6055 10” Scythe Stone 1 -/10

    truevalue hardware lists UPC
    Combination Sharpening Stone, 8 x 2 x 1-In.
    UPC 00082354060589
    Model Number 6058
    Gator Combination Sharpening Stone, 6 x 2 x 1-In
    UPC 00082354060602
    Model Number 6060
    Brand Gator
    Manufacturer Name ALI INDUSTRIES


    And then this guy brings it all together
    https://www.upcitemdb.com/upc/82354060589
    UPC 082354060589 is associated with Ace(r) Combination Sharpening Stone
    UPC 082354060589 has following Product Name Variations:
    8x2x1 Combination Stone
    Combination Stone
    ALI INDUSTRIES 6058 Combination Stone, 8-Inch x 2-Inch x 1-Inch
    Ali Industries 6058 Combination Stone - 8 x 2 x 1 in
    Ali Ind. 6058 Combination Stone-8" COMBINATION STONE
    Ali Industries 6058 Combination Stone 8
    Ali Industries 6058 8 By 2 By 1 Inch Combination Stone
    Ace(r) Combination Sharpening Stone
    Ali Industries 6058 Combination Sharpening Stone, 8 x 2 x 1-In.
    Ali Industries 6058 8 x 2 x 1-Inch Combination Sharpening Stone - Quantity 10
    Combination Sharpening Stone, 8 x 2 x 1-In.
    Ali Industries 6058 Combination Stone, 8-inch X 2-inch X 1-inch
    Ali Industries Combination Sharpening Stone, 8 X 2 X 1-in. 6058

    https://www.upcitemdb.com/upc/00082354060602
    UPC 082354060602 has following Product Name Variations:
    ALI INDUSTRIES 6060 Combination Stone, 6-Inch x 2-Inch x 1-Inch
    6x2x1 Combination Stone
    Ali Ind. 6060 Combination Stone-6" COMBINATION STONE
    Combination Stone
    Ali Industries 6060 Combination Stone 6
    Ali Industries 6060 6 By 2 By 1 Inch Combination Stone
    Ali Ind. 6060 6" Combination Stone
    Ali Industries 6060 6 x 2 x 1 in. Combination Stone
    Ali Industries 6060 Combination Sharpening Stone, 6 x 2 x 1-In.
    Ali Industries 6060 6 x 2 x 1 inch Combination Stone
    Combination Sharpening Stone, 6 x 2 x 1-In.
    Ali Industries 6060 Combination Sharpening Stone, 6 X 2 X 1-in. - Quantity 10
    Ali Industries 6060 Combination Stone, 6-inch X 2-inch X 1-inch
     
  20. HeavyHanded

    HeavyHanded

    Jun 4, 2010
    This is my YT channel, lately I've been putting up a lot more fitness stuff, but if you dig around there's a ton of sharpening content.

    https://www.youtube.com/user/Neuman2010

    My formerly top secret guided system the "MAGUKC" (multi angle guided universal knife clamp) aka 'it ain't magic!'


    and this one actually pertinent to the thread as it showcases my fav coarse stone in action
     
    willc likes this.

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