Announcement

Collapse
No announcement yet.

More fun with Cermets: Hard turning **FIRE**

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • More fun with Cermets: Hard turning **FIRE**

    I was hard turning a bearing race to make a one way clutch. It looked so cool I took some video as well as stills.









    Video in WMV format, 5.5 mb, 1 minute, good quality.

    http://ixian.ca/server/cermetfun.wmv
    Last edited by Evan; 07-09-2009, 10:55 AM.
    Free software for calculating bolt circles and similar: Click Here

  • #2
    Hi Evan
    Nice video. "Oneway clutch" Please make a thread of how to make one.
    You see I'm in need for one in the near future.

    Regards
    CS

    Comment


    • #3
      When it is finished I will post about it. Maybe tonight or tomorrow. I am currently working on about four things at once.
      Free software for calculating bolt circles and similar: Click Here

      Comment


      • #4
        Cool pics, can't wait to see the video.

        ME



        Edit: Ya the video was even better. Look forward to hearing the rest of the story.
        Last edited by Michael Edwards; 07-09-2009, 09:46 AM.

        Comment


        • #5
          Originally posted by crancshafter
          Hi Evan
          Nice video. "Oneway clutch" Please make a thread of how to make one.
          You see I'm in need for one in the near future.

          Regards
          CS
          Many bike starter clutches are made by spring-loading rollers on a very shallow slope pressing against the inside of a hard drum. Turn the drum one way and the rollers slide back up the slope, turn it the other and they are caught by the drum against the shallow 'taper'. They are very long lasting so long as they are kept well oiled. The same would work on a hardened shaft.
          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

          Comment


          • #6
            I was thinking you have the quietest SB 9" geartrain in the world, then I remember you have a d.c. drive on the tailstock end of your leadscrew.

            Comment


            • #7
              That was the little "click" and the quiet hum of thw PWM drive.

              Many bike starter clutches are made by spring-loading rollers on a very shallow slope pressing against the inside of a hard drum.
              Exactly. Except that you don't need the springs if you lubricate it with 3M traction oil. Traction oil lubricates very well for rolling contact but is very difficult to shear and does not permit sliding contact. It was developed for CVTs. It is also perfect for these clutches. I'm using some rollers from a roller bearing that was sacrificed to make a couple of these. 7 rollers per clutch with the ramps ground in the inner race. I've made these before and you need about .010 to .020 negative clearance (interference) between the OD of the inner race and the ID of the outer race. Uaually the ramps should be deep enough that the roller is stopped by a vertical face that meets it at the the midline. I'm experimenting with a slightly different design so I'm not quite sure how well it will work.
              Free software for calculating bolt circles and similar: Click Here

              Comment


              • #8
                Hi Evan.

                Are you sure it was cermet and not ceramic?

                Not trying to be critical, just curious.

                Comment


                • #9
                  Why do you need a one-way clutch?

                  I've been thinking about trying some hard turning. My K&T 2D has a proprietary taper - well the taper is NST 20 but it has a proprietary method of holding the taper in the socket because there is no drawbar. It is very hard to find the collets that go with it and I was thinking about ordering a ER32 collet chuck with a straight shank and then machining it to fit the taper.

                  This would require a significant amount of material removal and (obviously) I would want to test out my taper on a piece of scrap before cutting the taper on the actual chuck. Anyhow, what do you think about trying to remove such a large quantity of hardened material? My gut tells me it won't work too well, but the chuck I was going to sacrafice can be had from the import dealer for 14 bucks...

                  I've got some different carbide inserts, but I've also got 4 Kylon ceramic inserts. I was thinking about using the ceramic...


                  <edit> ExKenna - I expect Evan did mean "cermet" not "ceramic". They are two different materials. The cermet is a CERamic and METalic composition. They are supposed to be tougher (i.e. less likely to chip or break) than ceramic but be harder and have better high-heat hardness than tool steels.

                  <edited for ridiculous brain fart>
                  Last edited by Fasttrack; 07-13-2009, 04:02 PM.

                  Comment


                  • #10
                    It's a cermet insert from Kyocera.

                    Free software for calculating bolt circles and similar: Click Here

                    Comment


                    • #11
                      Fasttrack,

                      I think it will take a very long time and cost several inserts. However, I doubt that the material is hardened very deep. It is probably induction hardened and that doesn't extend throughout the material, maybe .1 to .2 inch or so and then becoming softer.

                      The one way clutches are for my hybrid trike. I have started work on it and will be posting about it fairly soon. I already have 2-3 kilowatt hours worth of battery power for it and a small brand new moped engine with about 1.5 kw output as well. Either or both power plants can run at once and the gas engine will recharge the batteries as needed. In town I will use only electric but for the hills I will use both. The main problem I have here is that a trip to town and back requires a total altitude gain of half a mile. You don't get much back through regeneration on the downhill sides. It's a good example of where a pure electric vehicle just won't make the grade, literally.
                      Free software for calculating bolt circles and similar: Click Here

                      Comment


                      • #12
                        First, my apologies to Evan. The purpose of my question was not to imply that you are ignorant of modern cutting tool technology, or even to hijack your thread. What has piqued my interest is your success hard turning with a cermet. White or black alumina ceramic products are typically chosen for hard turning apps. I can't find any reference to a grade in your posts but I suspect you are using Kyocera's TC30 which is a P05-P10 / K01-K10 grade not specifically intended for hard turning. The high hardness of this grade allowed this in your case but I suspect tool life would be unacceptable in a production environment. A65 or A66N would be a better choice as they are classified as H01-H10 grades for hardened materials.

                        I realize this may sound like splitting hairs but there is a lot curiosity about cermets. And a lot of misinformation.

                        Only recently have they overcome their tarnished reputation earned in the '70s, '80s, and early '90s. Dry machining was a new thing and early grades were prone to sudden and catastrophic failure. They became known as hard, brittle tools good only for finishing with light cuts. This has changed and the Japanese have led the way with progressively tougher grades that are becoming more and more accepted. We were so far behind at that time that almost all of our cermet/ceramics were bought under the table from Toshiba Tungaloy and NTK Ceramics and re-branded in the yellow and black packaging everyone recognizes. There have also been real quantum leaps such as Greenleaf's WG300 whisker reinforced product which turned this entire market niche on it's head. Think "fiberglass" for cutting tools.
                        One day I'll be able to share it's story: an improbable combination of ceramics, rice hulls, and the U.S Navy.

                        The Kyon grades are another story, be careful to do your research before using these. Pure ceramics and silicon nitrides are very application specific and just because it says "Kyon" doesn't mean it's suitable for hard turning steel. I have an interesting video of a test I ran milling Inconel at 1300 sfm. It looked like someone welding with the end of the spindle The part was an exhaust manifold for the Abrams tank.

                        Where was I ... Oh yeah, cermets.
                        Cermets are an answer to a question that no has asked yet. Their biggest selling point is a low affinity for carbon steels (eliminating BUE) which allows them to impart a beautiful finish approaching that of a ground part.
                        You can sometimes improve cycle time using them where a higher sfm is permitted but higher feed is not. This second advantage may be rapidly disappearing with the advent of carbide grades like Sandvik's 4205 (featuring Walter's PVD Al03 technology) which can run low carbon steels at 1200 sfm, with excellent tool life.

                        Be careful when touting them as "tougher than carbide". A quick glance at a few cermet grades will tell you that hardly any of them exceed P20, M20 or K10 on the ISO chart. The largest part of the carbide market is the P20-P30 range with the toughest grades extending all the way to P45.

                        Sorry for the long winded reply but I wanted you guys to understand the factors involved before rushing into this realm. Although Evan was successful using a cermet, ceramic is your first choice. You are plasticizing metal through the use of extremely brittle cutting tools in negative rake tool holders at very high surface footages. Rigidity of set-up and proper safety precautions are mandatory.
                        Last edited by exkenna; 07-10-2009, 01:53 AM.

                        Comment


                        • #13
                          I don't know if you saw my previous thread about these particular inserts but it was about the amazingly good finish these produce on low grade steel. One nice feature about these specific cutters is that there are 8 usable corners.

                          I have no illusions about what these can and cannot do and these aren't the first "exotic" cutting tools I have used. I have ceramic, PCD, and coated carbide inserts, solid carbide sticks 3 inches long, and a large selection of CBN and diamond grinding wheels.

                          When I find something new in this sort of cutting tool I usually push at least one sample to destruction to find out where the limits are. I will try them on the difficult to machine items such as abrasion resistant steel, hardened items of various alloys and torture tests with interrupted cuts in chilled cast iron.

                          I am always exploring new materials and ways to machine them. Right now I am looking for a way to machine a hole in C1 carbide. I don't have EDM (yet) but I do have a couple of grades of loose diamond grit.
                          Free software for calculating bolt circles and similar: Click Here

                          Comment


                          • #14
                            No Evan, I didn't see the previous post. I will search it out as I have been a cutting tool geek for 17 years or so and I like to see people experiment and make tools work to their advantage.

                            Those were nice pics, thanks for sharing.
                            If you like homemade videos here's one I shot a couple months ago during an end mill test.
                            If you get bored skip ahead to the 2:45 mark.

                            http://www.youtube.com/exkenna#play/.../3/_iVRrFKNtBU
                            Last edited by exkenna; 07-10-2009, 02:29 AM.

                            Comment


                            • #15
                              What were you cutting and what were you cutting it with? That's a pretty impressive doc and feed speed.

                              Comment

                              Working...
                              X