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Explain to me why precision stones

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  • Explain to me why precision stones

    Have to molest every surface a YouTube machinist is going to use? Is this the new normal? I watched someone stone their precision strait edge. precision square? stone it!

    There might be an upset on it! Stone it!

    Every one must get stoned..

    sam

  • #2
    Never fix a problem that you have not verified outside of your head. Don't assume!
    1973 SB 10K .
    BenchMaster mill.

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    • #3
      It's a fad

      I do keep stones at every work bench, but they are just cheap two sided things. Today I stoned the rust off a couple of spacer washers that are part of a centrifugal clutch that had locked up solid due to outdoor storage. I used ATF for the lubricant to "float the grunge" up off the stone. ;-)

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      • #4
        Originally posted by CalM View Post
        It's a fad

        I do keep stones at every work bench, but they are just cheap two sided things. Today I stoned the rust off a couple of spacer washers that are part of a centrifugal clutch that had locked up solid due to outdoor storage. I used ATF for the lubricant to "float the grunge" up off the stone. ;-)
        Ah yes, the crud scrubber!!
        1973 SB 10K .
        BenchMaster mill.

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        • #5
          I don't have any of them. I have no immediate plans to GET any of them.

          That said, I DO understand the point. And it is NOT a new one.

          The ground stones, as I understand them, are similar to my "burr files". They are not so much "preciaion", as they are made by actually grinding flats into the particles of the stone. That way they do NOT dig in to a surface, they glide across it.

          Same thing as the burr files, on a smaller scale.

          If it does not stick up, the stone does not bother it. If it DOES stick up, the stone cuts it off. So a "precision surface" (I HATE that description, btw) will not be damaged by the stone. Only things which stick up and make that surface less flat will be removed. Good for many things.... good for final cleanup when scraping, for instance.

          That is actually a valuable characteristic, and I totally understand and appreciate it.
          CNC machines only go through the motions

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          • #6
            A ground stone is still going to carry the tooth given it by the wheel used to grind the surface and also by the grain structure of the stone. I'd rather trust the burr file myself. The surface of my 6000x water stone looks and feels like polished ceramic. But it still cuts my knives and chisels to a mirror like shine.

            I understand how it will be a lot more aggressive on a burr. But I don't buy this idea that on a flat surface they don't cut at all.
            Chilliwack BC, Canada

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            • #7
              I do have a pair of them. And this description is quite accurate. They are made by grinding the peaks of the abrasive into flats. They not only glide over a flat surface, they glide over each other. When you take them out to use them the first thing you do is to rub them against each other to clean them. This is why they are supplied in pairs.

              When you rub them together, at the first stroke or two you can feel some resistance between them, some grit. But then, after just two or three strokes they just glide, much like a precision bearing. Almost zero resistance like floating on air. The brief resistance you felt at first was just some dust from the room that got caught between them. Once that is removed they are smooth as glass. And they can only remove something that sticks up above a flat surface. Once that has been done, they just glide across that surface and, even with a lot of force, they do not remove anything more.

              This is almost something that must be experienced for it to sink in. Before I got the ground stones, I thought that I could lap two or three stones together to produce the same effect. I even purchased three stones and tried that. I could not have been more wrong. No matter how much I rubbed the ordinary stones together, they still ground against each other. Session after session, they just continued to abrade each other. They may have become somewhat flatter, but they did not become precision ground stones. And if I had used them on a precision flat surface, unlike precision ground stones, they would have dug into it. It takes a high speed, diamond wheel on a surface grinder to produce the flats on each and every grain of abrasive in the stones. And probably a careful technique with that surface grinder.

              As far as I am concerned, they are one of the most valuable tools in my shop. I have used them on many things including 1-2-3 blocks, all of my squares, ground tools like milling vises, and others. And they can improve the surface of any part that has a surface that was milled flat. They can even be used on cylindrical parts with a rocking action.

              And if by "burr" files you mean files where the tips of the teeth have been ground flat, then yes, they are like that. But better.

              PS: They are not used to make a surface flat. That is for milling, scraping, surface grinding, and lapping. They are only to improve the finish on an already flat surface.



              Originally posted by J Tiers View Post
              I don't have any of them. I have no immediate plans to GET any of them.

              That said, I DO understand the point. And it is NOT a new one.

              The ground stones, as I understand them, are similar to my "burr files". They are not so much "preciaion", as they are made by actually grinding flats into the particles of the stone. That way they do NOT dig in to a surface, they glide across it.

              Same thing as the burr files, on a smaller scale.

              If it does not stick up, the stone does not bother it. If it DOES stick up, the stone cuts it off. So a "precision surface" (I HATE that description, btw) will not be damaged by the stone. Only things which stick up and make that surface less flat will be removed. Good for many things.... good for final cleanup when scraping, for instance.

              That is actually a valuable characteristic, and I totally understand and appreciate it.
              Paul A.
              SE Texas

              And if you look REAL close at an analog signal,
              You will find that it has discrete steps.

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              • #8
                Originally posted by BCRider View Post
                ...........................But I don't buy this idea that on a flat surface they don't cut at all.
                IF the stone is hard-textured, that is, the grit is held securely, and the particles are ground so that they have flats, then they actually will not cut.

                The key to the entire thing is that the particles are cut and polished. If that is not true, then all you have is a flattened stone.... one that may be very effective sharpening your pocketknife, etc.

                I originally did not understand what the deal was. Once I was clued into the fact that the actual grit is cut to have the flats, then I could easily see what the point was.

                If you "buy" the idea of the burr file, then you pretty much have to understand what is going on with the so-called "precision ground stones". If the burr file won't cut, the stone won't cut. If the stone will cut, then so will a burr file. You cannot escape that similarity.
                CNC machines only go through the motions

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                • #9
                  Its basically the same concept as the conditioning stones that are supplied with the high-end gage block sets. Those stones don't remove anything either, nor do they change the shape of the block. These stones simply apply the same idea on a much larger scale.
                  25 miles north of Buffalo NY, USA

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                  • #10
                    Originally posted by nickel-city-fab View Post
                    Its basically the same concept as the conditioning stones that are supplied with the high-end gage block sets. .........................
                    That was the "not a new idea" origin..... and I really need to get a conditioning stone for my P&W and B&S sets.... they need it. Thanks for reinforcing that in my mind..!
                    CNC machines only go through the motions

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                    • #11
                      A good flat stone (I cannot bring myself to call them 'precision') can do wonders for bringing in a surface when scraping. It will increase bearing without upsetting geometry. A non-flat stone (one that has not been ground flat) can drive you to suicide if you try to take such liberties and find you've rolled an edge all along it's length. I have several of them in different grades and a couple that have bevels ground into them to get in under dovetails. They help me a lot in terms of time saved.
                      Peter - novice home machinist, modern motorcycle enthusiast.

                      Denford Viceroy 280 Synchro (11 x 24)
                      Herbert 0V adapted to R8 by 'Sir John'.
                      Monarch 10EE 1942

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                      • #12
                        For me, most parts that go on the surface plate that are not slobbered in bluing get precision stoned. I have several sets around the shop. Tiers gives a good explanation of how they work. I would add that the stones not only remove small burrs but also dirt grime and oils from the surface. If you are measuring in 1/10s they are an absolute must to assure the parts are clean. Not critical if you are working in thousandths, but nice to have. I don’t know how I lived without them. Ignorance is bliss, I guess.

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                        • #13
                          YooToob, huh? Maybe the presenters are… wait for it… STONED!

                          You may throw tomatoes now.

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                          • #14
                            Originally posted by skunkworks View Post
                            Have to molest every surface a YouTube machinist is going to use? Is this the new normal? I watched someone stone their precision strait edge. precision square? stone it!

                            There might be an upset on it! Stone it!

                            Every one must get stoned..

                            sam
                            Yeah, problem is? Some folks dont know what the fuk they are talking about,,, Right?

                            I have stones from my concrete driveway to a perfect 12,000 Japanese stone. A lot of folks do. They may not know how to use a 12,000 ceramic stone. Oh well, I tried.. JR

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                            • #15
                              12,000 grit stone. I wrote the numbers on these stones/ She is very nice and smooth, 12,000 grit? Think about that... JR

                              And well the pile from 12k down =ward to 1k.

                              Oh and the wet fixing of the one plate? Yeah, that brown one does that. It will be flat now, It was not... J




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