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Some cermets

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  • Some cermets

    Picked up some old cermet inserts from bygone soviet times. Quite interesting and capable gadgets: TH-20 are a type of tungsten free hard alloy based on titanium carbide/nickel composite. Very light in comparison to a WC based insert of identical size. These work exceptionally good on aluminium alloys, brass, bronze and medium hardness steel. Always with a mirror finish. The BOK variety are a titanium carbide and complex oxide mix....these are meant exclusively for machining hardened steel. They even cut a hardened HSS threading die....
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  • #2
    with all these inserts you are love us!

    that's a crazily rounded edge on the insert in the holder, almost looks like it'll burnish/ melt the metal away rather than cut it. Are the ones for hardened steel the sort that you have to run them fast enough for sparks to fly or they don't work? (I might be thinking of another type though)

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    • #3
      Originally posted by mattthemuppet View Post
      with all these inserts you are love us!

      that's a crazily rounded edge on the insert in the holder, almost looks like it'll burnish/ melt the metal away rather than cut it. Are the ones for hardened steel the sort that you have to run them fast enough for sparks to fly or they don't work? (I might be thinking of another type though)
      True....they do have a rather special edge geometry. It's for reinforcement purposes as the ceramic material tends to be rather brittle. But they work very well on hardened materials at various rpm ranges even without a rigid machine. No chance on soft metals though. If I run them near 1000rpm or higher then I gotta make sure there are no flammable items around. Even managed to set my work table on fire once cutting a bearing race with one of these inserts.

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      • #4
        Originally posted by markx View Post

        True....they do have a rather special edge geometry. It's for reinforcement purposes as the ceramic material tends to be rather brittle. But they work very well on hardened materials at various rpm ranges even without a rigid machine. No chance on soft metals though. If I run them near 1000rpm or higher then I gotta make sure there are no flammable items around. Even managed to set my work table on fire once cutting a bearing race with one of these inserts.
        Good for you! Those are nice.

        I use all types of cutting bits from bad steel to cbn. The issue with ceramics is dont do interrupted cuts without the speed. Same with carbide and HSS.

        Use them. Nice tools. JR

        I forgot to add. I use these high speed bits mostly on my SB10l that maxes at 800rpm. I run it at about 750. JR
        Last edited by JRouche; 03-12-2020, 01:45 AM.

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        • #5
          Originally posted by JRouche View Post

          Good for you! Those are nice.

          I use all types of cutting bits from bad steel to cbn. The issue with ceramics is dont do interrupted cuts without the speed. Same with carbide and HSS.

          Use them. Nice tools. JR

          I forgot to add. I use these high speed bits mostly on my SB10l that maxes at 800rpm. I run it at about 750. JR
          The BOK-60 variety is actually very tough even in interrupted cut modes. When I machined the HSS threading die, it bashed against the flutes like nothing and absolutely no damage to the bit. There was also a bagful of white ceramic inserts included in the deal. These were sintered aluminium oxide and that variety was pretty much useless compared to the black ones....worked only on tremendous speeds and on very hard alloys. More of a grinding stone than a cutting insert really.

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          • #6
            Originally posted by markx View Post
            There was also a bagful of white ceramic inserts included in the deal. These were sintered aluminium oxide and that variety was pretty much useless compared to the black ones....worked only on tremendous speeds and on very hard alloys. More of a grinding stone than a cutting insert really.
            You know what, Im prolly turning too slow then for an interrupted cut.

            Yes. I have similar white and black inserts. Kennametal not Cermet but prolly similar. Same here, white ones are not working out for me. JR

            Click image for larger version

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            • #7
              Originally posted by JRouche View Post

              You know what, Im prolly turning too slow then for an interrupted cut.

              Yes. I have similar white and black inserts. Kennametal not Cermet but prolly similar. Same here, white ones are not working out for me. JR

              Click image for larger version

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              I probably confused people with the original title of the post.....the inserts are not of "Cermet" brand origin, but I refferred to them as generic ceramic-metallic composite or cermet for short. The inserts I have are of soviet production origin, but the functionality and purpose (also the generic composition I think) remain quite similar.

              But yeah, do try the white ones at max speed, as the ones I have tend not to work on speeds below 1000rpm. They snag and chew on workpiece and tend to catch the chip residue on the tip. They seem quite rough and have a rather coarse structure. The black TiC+oxide composites are super smooth and seem to have almost a uniform vitreous structure with no discernable grains....

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