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  • Carbide insert descriptions

    OK, can someone put on their secret decoder ring and decipher a couple of insert descriptions for me? I have 2 styles to describe, one is SDXT-90M405-NCM325 mf'd by Korloy Inc, the other is a CCMT 32.52-F3P PT20C NC3020 from Sowa Tool.

    The SDXT is a free cutting square insert that works well for me, the CCMT is a 60* or so diamnd insert that has performed like an absolute POS.

    The object of this exercise is to get a diamond insert that performs as well as the square ones...
    Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

  • #2
    One is a milling insert and the other is a turning insert. Different worlds.

    The Korloy is for milling low carbon and soft steels.

    The NC3020 is a turning grade for medium cutting of steel, not finishing.

    What are you using them for?
    Last edited by Glenn Wegman; 07-13-2009, 01:58 PM.

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    • #3
      Both inserts were supplied to fit holders that came with my lathe. Best recommendations from ACT.

      I asked for inserts for turning

      Most of the work is in mild or tool steel. Some mystery metal too.

      The holders have flat pockets that present the insert with the top face perpendicular to the work.

      So.. the milling insert outperforms the turning insert for hand and power fed turning and facing operations?????????!!!?....

      No wonder I'm frustrated!
      Last edited by camdigger; 07-13-2009, 02:14 PM.
      Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

      Comment


      • #4
        The "milling" insert (possibly dual purpose, but I believe listed as milling) most likely has a different edge prep than the turning insert in your case. Most likely a sharper edge and possibly more "top rake" just behind the cutting edge? The turning insert most likely has a "duller" edge due to it not being a finishing insert.

        Just a guess!

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        • #5
          Like Glenn says, the SDXT is a square high positive (11°) milling insert. You could certainly use it for a turning insert, but I think you'd be better off with the CCMT, which is a 7° positive turning insert.


          the CCMT is a 60* or so diamnd insert that has performed like an absolute POS.
          It's an 80° diamond, which is nice because you can turn and face without moving the insert. CCMT's are pretty popular with HSM'er's. Korloy makes good inserts, but I'm not familiar with "Sowa Tools." You might try a name-brand (Kennametal, Sandvik, Valenite) insert...
          Last edited by lazlo; 07-13-2009, 02:44 PM.
          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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          • #6
            Originally posted by lazlo
            Like Glenn says, the SDXT is a square high positive (11°) milling insert. You could certainly use it for a turning insert, but I think you'd be better off with the CCMT, which is a 7° positive turning insert.
            The SDXT is being used in a 45 degree holder which allows both turning and facing, but will not cut a shoulder. I can cut .004 IPR and apply a DOC that will throw a chip 0.200 wide at 400 RPM on a 1" MS rod without complaint.

            The CCMT diamond inserts are reserved for shoulder cutting in a +/- 20 degree holder that's supposed to allow both rh turning and facing. I say reserved because of the P!$$ poor performance of the CCMTs. The lathe complains so much, I'm reluctant to even use a power fed with them.

            FWIW, SOWA Tools seem popular up here as both ACT and Thos Skinner and Son recommend them above some others.

            From the SOWA Tool website, the CCMT has a 0 degree rake land behind the cutting edge and a chip beaker groove behind. The tip radius is 1/32". I haven't found the SDXT insert yet...
            Last edited by camdigger; 07-13-2009, 02:56 PM.
            Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

            Comment


            • #7
              Originally posted by camdigger
              From the SOWA Tool website, the CCMT has a 0 degree rake land behind the cutting edge and a chip beaker groove behind. The tip radius is 1/32". I haven't found the SDXT insert yet...
              Well there you go!

              Try it on a .030" doc at high spindle speed and you'll see a big improvement in the finish. That's what it's made for.

              Glenn

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              • #8
                Glenn

                Any suggestions as to IPR it should handle.. What SFPM? High spindle speed is a relative term and highly dependent on workpiece size.. All I know it is a POS at the settings the SDXT handles without complaint.

                Cam

                Any idea if the SDXT has a land behind the cutting edge? If so, how wide? FWIW, I've also used a TNMG insert with fair results.
                Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

                Comment


                • #9
                  Originally posted by camdigger
                  From the SOWA Tool website, the CCMT has a 0 degree rake land behind the cutting edge and a chip beaker groove behind.
                  Ah, that means you need to take a DOC that's deeper than the land width to get a positive rake angle. If your DOC is equal to or less than the land width, you've effective got a negative rake insert.

                  You should really try another brand of CCMT insert.
                  "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                  Comment


                  • #10
                    The CCMT has 7 degrees of clearance. That doesn't make it a positive insert, especially in light of the manufacturer description that says the cutting edge is at zero degrees. Since your tool holder is also at zero degrees it is absolutely essential that the cutting edge be either no higher than centre line AT ALL or even slightly lower than centre line. I would drop it just slightly under centre and run the sfm at three times HSS.
                    Free software for calculating bolt circles and similar: Click Here

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                    • #11
                      Ah, that means you need to take a DOC that's deeper than the land width to get a positive rake angle.
                      Nonsense Robert. That won't make the cutting edge positive.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        Originally posted by Evan
                        Originally posted by Lazlo
                        Ah, that means you need to take a DOC that's deeper than the land width to get a positive rake angle.
                        Nonsense Robert. That won't make the cutting edge positive.
                        It makes the cutting edge a lot less positive if you don't take a DOC that's greater than the land length -- because the chip isn't making it to the chipbreaker.
                        If the insert is tilted down 5° like most CCMT inserts are, it will literally turn a positive rake insert into a negative rake insert.

                        But you still don't understand negative rake inserts, so I doubt you'd understand this nuance.

                        From Plastools:
                        http://www.plastools.com/insert_information.htm


                        Figure 2 depicts three very basic Rake Surface Angles which would be regarded as major elements of the topography. The land length shown in figure 2 are somewhat misleading in that the transitions to the chip control groove and the groove itself is smooth rather than harsh angles as shown in figure 2,
                        a positive rake surface is possible with the TNMG-XXX insert if the DOC is greater than the cutting edge land length.
                        Last edited by lazlo; 07-13-2009, 03:35 PM.
                        "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                        Comment


                        • #13
                          It makes the cutting edge a lot less positive if you don't take a DOC that's greater than the land length -- because the chip isn't making it to the chipbreaker.
                          If the insert is tilted down 5° like most CCMT inserts are, it will literally turn a positive rake insert into a negative rake insert.

                          But you still don't understand negative rake inserts, so I doubt you'd understand this nuance.
                          You are not reading what the OP wrote. The cutting edge isn't positive at all regardless of depth of cut.

                          His tool holder is zero rake. The cutting edge has a land that is zero rake. That insert has a suggested DOC of as little as .008". That isn't going to turn it into a positive rake edge. There is no reason to tilt it down since it already is supplied with a 7 degree clearance angle. The insert is designed to cut with a zero degree cutting angle with a 7 degree clearance angle. Suggested speed is 850 to 900 sfm for low grade steels.
                          Free software for calculating bolt circles and similar: Click Here

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                          • #14
                            Originally posted by camdigger
                            Glenn

                            Any suggestions as to IPR it should handle.. What SFPM? High spindle speed is a relative term and highly dependent on workpiece size.. All I know it is a POS at the settings the SDXT handles without complaint.
                            Sorry about that, should ave been more specific.

                            I don't know what you have for spindle speed or HP. Depending on part dia, you may not get near this sfm.

                            400 to 600 sfm in mild steel, if it's coated probably more. Try .003 to .005 ipr at .020 to .030 doc and see what you get. It's pretty light for sure as far as feed, but I understand that you are looking for finish. A spritz of coolant may help too. If not good, try more, or less. I'm just guessing as I don't have the specifics on the insert.
                            Last edited by Glenn Wegman; 07-13-2009, 03:52 PM.

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                            • #15
                              Originally posted by lazlo
                              Ah, that means you need to take a DOC that's deeper than the land width to get a positive rake angle. If your DOC is equal to or less than the land width, you've effective got a negative rake insert.

                              You should really try another brand of CCMT insert.
                              If DOC is transverse to the main axis of the work when doing R to L turning, I rarely go less than 0.020" unless I'm turning to a finish diameter. With the SDXT inserts I go about 0.030 - 0.060" for fast stock removal. I don't recall for sure, but I think I had the IPR set about 0.004".

                              At a list price of over $8 per insert, and HSS blanks at +/- $5 per, I can't justify too many experiments.

                              I'd like to find out how wide the land is on the CCMT insert vs the land width on the SDXT but I can't find the spec on either one.

                              As it sits, the land converts the CCMT insert into a 0* rake insert
                              Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

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