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Thread: Flattening waterstones

  1. #1
    Join Date
    Sep 2019
    Location
    Lafayette, CA
    Posts
    372

    Flattening waterstones

    I'm guessing this topic has been visited and revisited over and over on SMC, but I'm still new here so I'll ask my question anyway.

    I flatten my Norton and King waterstones on wet/dry 220 grit sandpaper on a granite surface plate. Now that I'm sharpening much more regularly, I'm going through sandpaper sheets at a noticeable pace. I'd always heard that in the long run sandpaper is more expensive than other methods, but that was less relevant when I was sharpening less frequently.

    I did hear on this site that folks discouraged me from looking into the Norton flattening stone, so my plan is to continue with the wet/dry paper (plus, I already have the surface plate). The five-sheet packs are 7 or 8 dollars, though. I want to choose one brand and buy the largest pack I can find (probably 100 sheets), so I don't want to get stuck with something that doesn't work well.

    Who can help me make sense of the variables here? It looks like silicon carbide may be better at this grit than aluminum oxide. Agree? This is just for the waterstones. For me the other attributes that matter are: easy to reuse, gets flat again the next time on the plate, lasts through several flattenings, doesn't slide on the plate, and resists bunching up. Finally, I'd like to get the price down below $1 a sheet.

    Any other wisdom is welcome, even the contrarian view on the sandpaper method.

  2. #2
    Join Date
    Aug 2014
    Location
    Silicon Valley, CA
    Posts
    639
    Lots of options.

    Classic cheap is dry wall screen. It's an open mesh so it won't load as fast as sand paper. That said, it too adds up over time.

    I think most people end up with a diamond plate. It costs more up front, but lasts so much longer for stone flattening it's eventually cheaper. You can go real cheap with generic plates, e.g. Amazon Marketplace direct from China, but while some folks have happy, others have reported serious flatness issues. You can go really expensive, e.g. DiaFlat, Shapton, Nanohone etc, and pay a premium for better than you really need. Though many that have gone that route rave about the quality. IMO- the sweet spot is in between. The standard "go to" plate is an Atoma 140 or 400. You can get them in reasonable size off of Amazon for $65-75 these days. (Used to be Stu's Tools from Japan was the only reasonable source in the US, but he's closed down and other vendors have filled in.) I think the store brand flattening plate from Japanese Knife Imports is an even better choice for flattening. I trust Jon, the owner, to ensure quality control and can vouch the plate does it's job easily and well. For $55 it's the cheapest I know of (without the no-name lottery on Amazon or eBay) and it's in stock:

    https://www.japaneseknifeimports.com...attening-plate

  3. #3
    I use a DMT diamond plate. I find it produces an adequately flat stone. They last a very long time - I've had, and used, mine for at least 10 years and it still works fine for flattening my Shapton stones.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  4. #4
    Join Date
    Dec 2010
    Location
    South Coastal Massachusetts
    Posts
    5,718
    Auto supply or Grainger should offer coarse wet/dry sandpaper at reasonable cost.

    Your next nearest solution is a large diamond plate.

    If you're like most of us, a hobbyist, sandpaper to occasionally flatten a stone shouldn't be pricey.

    You can probably wash the sheet off, between uses.

  5. #5
    Klingspor woodworking shop has 50 sheet packs of SC wet/dry. Their stuff is generally good quality.
    --Certainty is the refuge of a small mind--

  6. #6
    Join Date
    Aug 2019
    Location
    Pittsburgh, PA
    Posts
    118
    I use silicon carbide grit from Lee Valley on a piece of thick glass. I get my carborundum and washitas flat faster than using sandpaper.

  7. #7
    Join Date
    Apr 2013
    Location
    Stone Mountain, GA
    Posts
    594
    If you are doing enough sharpening that the sandpaper is expensive/annoying then go for a diamond plate.

    A diamond plate is useful for other things too, for when you need a very hard surface stone or need to cut HSS or carbide, etc.

  8. #8
    Join Date
    Feb 2014
    Location
    Lake Gaston, Henrico, NC
    Posts
    4,861
    I have Atoma replacement sheets-140 and 400-on a granite surface plate. I think they are 100x200 mm, or about 4x8 each. I used sandpaper for a long time, and then bought some Diamond plate(forget the manufacturer) that wasn't flat, so I went with a surface I know to be flat.

  9. #9
    I think sandpaper is too much time and effort -- much more convenient to use a diamond plate. Make sure it's flat, though. I've had DMT plates and a Trend plate that were not quite flat, and it can result in a lot more work sharpening, and poor results. Best to get one from a retail store where you can return it if it's not flat.

    Another option: if you don't want to spend much money, you can make flattening stones out of bricks. You'll need three of them, plus some silicon carbide powder. They will be extremely flat. I made a thread about it here: https://sawmillcreek.org/showthread....-with-3-bricks

    One thing to note about the bricks: In the sharpening guide where I read about the idea of using three bricks, the author recommended cutting grooves in them with an angle grinder. I don't have an angle grinder, so I didn't cut grooves in the bricks, and I eventually started having issues with stiction.

  10. #10
    Iíve read that getting a matching pair of stones and rubbing them together is the best way to get them flat without making them cut coarser or finer, but you have probably read that too. It seems like with anything related to sharpening, the thing to do is pick a way and get good at it, and thatís another thing youíve probably read.

  11. #11
    Join Date
    Aug 2014
    Location
    Silicon Valley, CA
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    639
    Quote Originally Posted by Mike Cornwall View Post
    ... pair of stones ....
    Using two doesn't make them flat, it makes them complementary surfaces often with one concave and one convex. To insure flat you need three stones and you rotate them so each matches the other two.

    Trust me, a decent diamond plate is much less mess and hassle.

  12. #12
    Quote Originally Posted by Mike Cornwall View Post
    I’ve read that getting a matching pair of stones and rubbing them together is the best way to get them flat without making them cut coarser or finer, but you have probably read that too. It seems like with anything related to sharpening, the thing to do is pick a way and get good at it, and that’s another thing you’ve probably read.
    David's right. With two stones you get two conforming surfaces which will most likely be one concave and one convex. You can get a flat surface using three stones and a specified rotation when you rub two at a time together.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  13. #13
    Join Date
    Dec 2016
    Location
    South West Ontario
    Posts
    1,057
    Have used a diamond plate for years, it is not much larger than the stones so I bought a larger double sided CBN plate, certified crazy flat. The coarser side is very aggressive, the fine side works well, the increased size feels good. I used both today, the CBN plate is faster. You need to put it somewhere warm and ventilated to dry or it will rust. The other benefit is the coarse side can be useful for other re-shaping projects for rapid removal.
    ​You can do a lot with very little! You can do a little more with a lot!

  14. #14
    Two stones are sufficient if you know what you are doing. If you are just going to rub mindlessly while watching television, yes you can end up with one slightly concave and one convex. Invariably, however, both stones are slightly concave so they can be improved by matching up their high spots. And if you start to get one stone somewhat convex, you can alter your rubbing pattern.

    Day to day, the danger is having a stone concave across the width. This we can manage by how we sharpen: letting a plane iron or chisel hang over the edge will cause the wear to even out.

  15. #15
    Iíve read those things, as well. I hope everyone has found or is about to find the gear that answers all his prayers.

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