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some diamond wheel questions

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  • some diamond wheel questions

    I don't even know if this is okay/normal/adequate, but I would like to mount some kind of diamond wheel on my 8" bench grinder. I'm really only interested in it to allow me to freehand grind some cutting tool oddities out of broken carbide EM's. I have long been making various cutting widgets from ruined HSS em's. The other day I was rummaging through my broken stuff and couldn't come up with a HSS piece to save my life, I had to grind my tool out of a previously modified HSS EM that I was saving in case I ran into the same job again-- you get the idea...

    I accumulated a lot of solid carbide EM's on a trade a few years back, and also at auction. I recently broke a $hit ton of it on the CNC because my ER32 chuck had a depth setting plug I did not know about slowly back out and kept my collets from seating fully. I literally broke probably $400 (retail) worth of tooling in one afternoon before I figured out what was up, and that was still pure chance as the depth plug backed out far enough that I couldn't seat a collet at all anymore-- it was one of those smack yourself in the head moments!

    Anyhow, now I have a lot of junk carbide which would be great to make cutting widgets from. I don't own a cutter/grinder, I'd be happy to be able to free hand grind them like I do HSS. Is there a reasonably priced diamond wheel I can mount on a bench grinder? What is recommended? I know nothing about them. Links are appreciated if you know of something that will do what I want.

    Thanks!
    Jason

  • #2
    So, was this just a really stupid question? I have tried to answer my own questions, but I am not turning up anything like what I envisioned... Just a diamond coated wheel to take the place of a AO wheel on a bench grinder. Is there something out there? Will it not work like I want?

    Thanks,
    Jason

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    • #3
      Originally posted by jacampb2
      So, was this just a really stupid question? I have tried to answer my own questions, but I am not turning up anything like what I envisioned... Just a diamond coated wheel to take the place of a AO wheel on a bench grinder. Is there something out there? Will it not work like I want?

      Thanks,
      Jason
      Not a stupid Q at all. I tend to re-sharpen everything I can get ahold of. I have a variety of diamond wheels. Some narrow wheels on the bench grinder that I use strictly for TIG electrode grinding but it would also work to shape a carbide EM. The wheels are pretty fine though so they dont actually remove much material.

      Then I have one of the inexpensive carbide grinders, the Baldor copy. I have two diff grits of diamond wheels on it. Thats the ticket!! Two diff. grades or grits, not sure how they call the diamond grits. But one does the roughing and the other does the semi final sharpening.

      They are nice cause the cutting is done on the flat surface. Not the radius of the wheel. I can control the shape better.

      Then I will take it to the accu-finish grinder (lap machine) and polish up the edge.

      If Im not in a hurry, or have a few to do Ill set up the cuttermaster to do some grinding. I usually keep a HSS wheel on it though so I have to swap out the wheel for a diamond cup. I dont usually do that for custom grinds though. Its not as "free hand" as the carbide grinder. Its set up with tool holders or end mill holders. And it really is for cutting a pre-determined shape, not for odd ball grinds. But it is useful for turning a chipped carbide EM into something that is usable again..

      Prolly the best advice I could give is wear a quality mask. I like 3M. But really. Grinding carbide produces some awful dust. From the carbide and the diamond wheel. And that goes for HSS grinding also. Some really bad dust in the air from any of those metals. And dont forget the eyeballs too K,,, Nuff with the OSHA type talk, Im sure you know not to breath carbide dust.

      Definitely regrind your broken bits.. The is alot of useful material there. JR
      My old yahoo group. Bridgeport Mill Group

      https://groups.yahoo.com/neo/groups/...port_mill/info

      Comment


      • #4
        The best way to grind carbide is with a diamond wheel.
        However, you have to use lubrication. Water is good. Oil works but is messy.
        If you don't lube, your wheel will not last long. It will burn up.
        Some folks on the forum may have had some success without lubrication but I would bet that their wheels have not seen hard use. The diamonds seem to "burn" without lube or steel, etc.
        With lubrication, your wheel will last a lifetime with limited, home shop use.
        You don't want too coarse a wheel or it will chip your carbide (80-180 for ex.).
        Too fine a grit (1200 or up) will cut slowly but leave an excellent finish.
        Perhaps about 300 to 600 would do the best all-around job.
        A simple drip tank setup will work for wetting the wheel while you are working.
        Vitَria, Brazil

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        • #5
          Another quick thought.

          A set of diamond files work well for final sharpening and shaping.

          Since they work slowly, they will not need so much lubrication.
          Vitَria, Brazil

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          • #6
            It seems no ones commented on your question about getting a wheel for a bench grinder -- something I have also been thinking about trying to set up. It would seem that all the configurations in diamond wheels I can find - in the cheap ones - all have the 1-1/4" hole. So I'm thinking if I have to make up an adapter to utilize the big hole I'll go for the wheel thats used on the Baldor type grinders. As Rouche mentioned the flat face on it would allow more free movement, especially with out the table, giving access to the full 360* of the wheel surface.

            Shouldnt be a big deal to turn up a piece of aluminum to fit the shaft of a bench grinder and the flat back of one of those wheels. The 2 'cheapie' sites that have the wheel are Shars & CDCO, with CDCO offering 3 grits (fine 320, med 180 coarse 100) and Shars only in 150 grit.
            If everything seems to be going well, you have obviously overlooked something........

            Comment


            • #7
              Consider how long it will take a fine diamond wheel to cut any appreciable amount of carbide away. Do you think you'd get anywhere with a 220 grit regular grinding wheel on regular steel? I hope you don't find you have wasted your money.

              Comment


              • #8
                Originally posted by gwilson
                Consider how long it will take a fine diamond wheel to cut any appreciable amount of carbide away. Do you think you'd get anywhere with a 220 grit regular grinding wheel on regular steel? I hope you don't find you have wasted your money.
                I'm sure that the wheel I am using is finer than 220 grit. On top of that, it is a used wheel I "stole" from my son's lapidary business. It takes me no time at all not only shape a carbide bit, but to put a good edge on it.

                Having said that, if you can find a used wheel or one that you can take the initial sharpness out of with a piece of rock or something, perhaps a wheel such as 180 could be made to work. I wouldn't consider anything less than that, and even so, it could be "chippy."

                I'm using a little motor to turn my wheel that I took off a table top drill press when I traded it for a variable speed treadmill motor.
                Vitَria, Brazil

                Comment


                • #9
                  Thanks guys! I have no issue with adapting the arbor, what I wasn't finding was a wheel that was just a wheel. I found cups and rounded face stuff, but I didn't even know where to look. Enco has some stuff that looked like what I am interested in, but they want about $300 for one, I don't think a little experiment is worth that money, not unless one of you guys already uses this method. Thanks again for the input.

                  Jason

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