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  • #31
    Originally posted by lugnut View Post
    Plunger, about this time last year I posted my version of a diamond wheel carbide sharpening setup. https://bbs.homeshopmachinist.net/fo...-sharping-tool
    some liked it some made fun of it, but it worked out great for me.
    Nice..... I have tha same wheel on a shaft/ lathe for some grinding needs. I also have steel / brass brush wheels, for quick n dirty work. That's why we enjoy this forum!!

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    • #32
      Originally posted by plunger View Post

      This is what Im trying to find out. A good grit for sharpening carbide not shaping.
      I think Doozer slipped a digit, or he's putting some kind of finish on them. 150 grit is norm, what mine are. A quick look at machinist catalogue doesn't show grits over 220. With 150 you can put close to a mirror finish on things....remember the finish is partially grit and partially, I'll call it sampling rate - the averaging of all the grits whirling across the surface. Most/many hardened ground surfaces you see would be done with say 46 grit wheel but you can get a fantastic finish by sparking out and the averaging it creates. Its no fun using a finer wheel than needed

      https://www.mcmaster.com/diamonds/to...-type~type-11/
      Last edited by Mcgyver; 08-24-2021, 06:18 PM.
      in Toronto Ontario - where are you?

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      • #33
        Aren't diamond "stones" used for hand sharpening knife blades? Doesn't that mean that you can use diamond on steel if you keep the temperature down to the point where you are not burning the diamond (which is just a form of carbon)?

        Either use water to keep the temperature low or use a slow speed. Or both.

        Or am I completely wrong on this?



        Originally posted by nickel-city-fab View Post
        What if I have a brazed carbide tool that i want to re-shape? Then I need two different grinders? I thought you couldn't do steel on diamond?
        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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        • #34
          I have a cheap 4" resin bonded cup wheel like this:
          Click image for larger version

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          The resin looks to be about 1/4" thick - are there diamonds throughout that thickness? If so, how are new diamonds exposed? I.e., how is the wheel dressed? If not, I guess that there's no telling how deep the diamonds actually are, given that it's a cheap wheel.

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          • #35
            Originally posted by Mcgyver View Post

            I think Doozer slipped a digit, or he's putting some kind of finish on them. 150 grit is norm, what mine are. A quick look at machinist catalogue doesn't show grits over 220. With 150 you can put close to a mirror finish on things....remember the finish is partially grit and partially, I'll call it sampling rate - the averaging of all the grits whirling across the surface. Most/many hardened ground surfaces you see would be done with say 46 grit wheel but you can get a fantastic finish by sparking out and the averaging it creates. Its no fun using a finer wheel than needed

            https://www.mcmaster.com/diamonds/to...-type~type-11/
            I think Doozer has it right. I'm surprised most of you think 150 grit will give a good enough surface. I use 3000 to finish.

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            • #36
              Originally posted by eKretz View Post
              Green silicon carbide wheels "work," but not very well compared to diamond wheels. Pretty much night and day difference. There's no way to tell which Chinese wheels will be good and which won't without trusting reviews. I have had better luck with the Russian or Ukrainian diamond wheels, which can be had on eBay.
              Right - because if you can't give your money to china then of course the next place to support is of course russia... it's all making perfect sense now...

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              • #37
                Originally posted by Bob Engelhardt View Post
                I have a cheap 4" resin bonded cup wheel like this:
                Click image for larger version

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                The resin looks to be about 1/4" thick - are there diamonds throughout that thickness? If so, how are new diamonds exposed? I.e., how is the wheel dressed? If not, I guess that there's no telling how deep the diamonds actually are, given that it's a cheap wheel.
                Yeah, the diamond should be mixed evenly through out the resin. I think the manufacturing process is akin to mixing chocolate chips through cookie dough. You can go light on the amount of chips you put in, but it will tend to be mixed more or less evenly in suspension. Better and more expensive wheels will note the concentration of diamond in the wheel also. CCC wheels, can be anybody's guess.

                When I switched us to the resin bonded diamond wheel, we did try to dress them at first. We would use broken carbide endmills. But because the wheels are so light, we just kind of stopped bothering to dress them. Vibration was of no issue with the Darax.

                If the wheel runs smooth, as you grind with them, you can see tiny sparkles of diamond in the dust as the wheel slowly breaks down.
                If you think you understand what is going on, you haven't been paying attention.

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                • #38
                  Thanks for the heads-up, I really didn't know. I've been wanting to try a diamond wheel for a while now, but i have absolutely zero knowledge or experience with them.

                  Originally posted by Paul Alciatore View Post

                  Either use water to keep the temperature low or use a slow speed. Or both.

                  25 miles north of Buffalo NY, USA

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                  • #39
                    Originally posted by nickel-city-fab View Post
                    Thanks for the heads-up, I really didn't know. I've been wanting to try a diamond wheel for a while now, but i have absolutely zero knowledge or experience with them.
                    ok, the whole diamond and steel comes from the fact that the local temperature reached can cause the diamond (carbon) to be absorbed by the steel. When the only options were very expensive diamond wheels, this mattered. John Stevenson (can't believe its been almost 4 years since he passed) claimed he used cheapo diamond wheels on steel for ages and they still worked...and if you weren't spending a ton on them what did it matter if they wore a tiny bit on steel? That's the why on diamond and steel, and also the why the wind maybe taken out of the sail a bit on "don't" position.

                    The temps we are talking about is where a microscopic bit of diamond collides with a bit of work. That temperature is almost entirely depended on the relative speed and coolant or water will do about nothing to change it. Coolant does stop heat build up, flushed chips away, keeps particles out of the air (but adds others) keeps the wheel clean, lubricates where there is friction etc...I wouldn't want to grind anything without coolant its just so much better with.....but if the diamond absorption while grinding steel (at whatever rate) is your concern, coolant won't stop it. Slowing way down will.....or better yet, get the right tool for the job - a CBN wheel. Do use a diamond on carbide.

                    Brazed tools? What's that? j/j. I might try to under cut the steel on a regular wheel then use the diamond wheel, or more likely just have it with the diamond and loose a bit of wheel life. No way would I use the green wheels, too rough an edge
                    Last edited by Mcgyver; 08-25-2021, 05:21 PM.
                    in Toronto Ontario - where are you?

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                    • #40
                      Originally posted by Mcgyver View Post
                      Slowing way down will.....or better yet, get the right tool for the job - a CBN wheel. Do use a diamond on carbide.

                      Brazed tools? What's that? j/j. I might try to under cut the steel on a regular wheel then use the diamond wheel, or more likely just have it with the diamond and loose a bit of wheel life. No way would I use the green wheels, too rough an edge
                      Could I get away with just a CBN for both carbide and steel at a slow RPM? Using a spray bottle for cooling.
                      Yeah, I got a deal on a dozen AR-style brazed bits a while back, was thinking to grind them into whatever special shape.
                      Also started saving my old inserts.
                      25 miles north of Buffalo NY, USA

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                      • #41
                        Originally posted by elf View Post

                        I think Doozer has it right. I'm surprised most of you think 150 grit will give a good enough surface. I use 3000 to finish.
                        a 3000 grit wheel? I'm talking grinding as in a cup wheel on a tool grinder, not those pads for the slow turn things. If so, first question, why, 150 puts a mirror like finish on, and 2nd, where do you get them? I looked in a few tool catalogues, nothing over 220.
                        Last edited by Mcgyver; 08-25-2021, 05:29 PM.
                        in Toronto Ontario - where are you?

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                        • #42
                          Originally posted by A.K. Boomer View Post

                          Right - because if you can't give your money to china then of course the next place to support is of course russia... it's all making perfect sense now...
                          I support whoever makes decent product that I don't have to worry about needing to chuck in the trash bin when it arrives. I don't care where it comes from for the most part. I care that it works. You sure like to rant a lot... Not sure exactly why you would care what anyone else uses or doesn't. This kind of attitude is what makes politics such a pain in the arse. Don't like those either.

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                          • #43
                            Yes, use water if at all possible to help the diamond wheel and work piece stay clean and cool
                            We added a small amount of liquid soap to make the water wetter and stay on the wheel ( if possible)
                            Not a bad idea to have a vacuum system take away the carbide particles
                            Rich
                            Green Bay, WI

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                            • #44
                              Originally posted by nickel-city-fab View Post

                              Could I get away with just a CBN for both carbide and steel at a slow RPM?
                              I've not done it but apparently it can work, just that the CBN does not work as well cutting the carbide as diamond. afaik no need to go slowly, CBN is ideal for steel
                              in Toronto Ontario - where are you?

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                              • #45
                                Originally posted by Mcgyver View Post

                                a 3000 grit wheel? I'm talking grinding as in a cup wheel on a tool grinder, not those pads for the slow turn things. If so, first question, why, 150 puts a mirror like finish on, and 2nd, where do you get them? I looked in a few tool catalogues, nothing over 220.
                                Flat lapping disks. I suspect the tool surface finish required to cut wood cleanly may need to be much better than for metal
                                Click image for larger version

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