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  • attn Piranha owners, a question...

    Before when I heard everybody singing the praises of the Piranha I assumed that you just stuck a piece of tungsten into this magical machine and it did the rest. I finally got to see a few pictures and it appears to be a much more manual process. It looks like you have to do the taper and the flat separately and I'm guessing spin the tungsten by hand while it grinds the taper? The biggest thing I'm concerned about is the flat. I don't see any way for it to do a specific flat width over and over again. I see that it has the angle that you can dial in to get an exact taper, but how do you specify that you want exactly a .020" flat? It looks like you are just sticking the tungsten straight in from the side, perpendicular to the wheel, and how much or how little gets ground off would be completely up to the operator. But I'm thinking that almost can't be the case, can it?


    Thanks,
    Jeff

  • #2
    I think someone should invent a simple tungsten sharpener that works like a crank pencil sharpener.

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    • #3
      Originally posted by 2JZfan
      Before when I heard everybody singing the praises of the Piranha I assumed that you just stuck a piece of tungsten into this magical machine and it did the rest. I finally got to see a few pictures and it appears to be a much more manual process. It looks like you have to do the taper and the flat separately and I'm guessing spin the tungsten by hand while it grinds the taper? The biggest thing I'm concerned about is the flat. I don't see any way for it to do a specific flat width over and over again. I see that it has the angle that you can dial in to get an exact taper, but how do you specify that you want exactly a .020" flat? It looks like you are just sticking the tungsten straight in from the side, perpendicular to the wheel, and how much or how little gets ground off would be completely up to the operator. But I'm thinking that almost can't be the case, can it?


      Thanks,
      Jeff
      I have a PIII and you are correct that the taper and flat are two separate steps. You spin the tungsten by holding it with the supplied pin vise or you can use a small cordless drill. As far as the size of the flat, I have NEVER pulled out my caliper to measure the exact size. Instead, I do it by eye and can instantly tell whether is it too big or too small. All it takes is a little preactice (as does anything) and you will have it down. I wholeheartedly endorse the DG Pirhana grinders and while they certainly are not a necessity for most, I would not give mine up.
      Dynasty 350DX
      Dynasty 200DX TigRunner
      MM 350P
      MM Passport Plus
      Spectrum 375 Extreme
      08' Trailblazer 302

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      • #4
        I have a PIII and love it. I would not trade it for any type of "autotmatic" pencil sharpener. The flats are repeatable by a simple depth measuring device mounted on the top of the machine. It does take a bit of practice, but I prefer to eyeball and feel the touch to get my flats.

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        • #5
          ok, thanks for the responses guys.

          speaking of flats, the sample Tri-Mix and Cryo-T tungstens that they sent me are ground to what looks like a needle point. They say its actually a .005" flat. They claim that will handle high amperage but that seems crazy to me, I'll have to try it. Right now I'm using 1.5% lanthanated that I got from TigDepot (3/32) and around 180-200 amps it seems that the tungsten is spitting and deteriorating. So I ordered 2% lanthanated from DG because that is supposed to handle more heat right? When I was preparing the 1.5% tungsten, I was using about a .030" flat and it was still spitting, does that seem right (Dyn 300, 65% bal, 120Hz, Argon, 180A AC)?

          Also, on the two grinding steps, I always do the flat first, then the taper, but every time I read about it, the person says grind the taper, then add a flat. My thought was that if you added the flat last, you would have a "lip" extending off the side of the taper like you do with any grinding. Is that not a valid concern?

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          • #6
            CHECK OUT THE VIDEOS
            http://www.diamondground.com/productover.html#grinder
            Dynasty 300DX
            Miller Matic 35
            Piranha II

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            • #7
              Originally posted by 2JZfan
              speaking of flats, the sample Tri-Mix and Cryo-T tungstens that they sent me are ground to what looks like a needle point. They say its actually a .005" flat. They claim that will handle high amperage but that seems crazy to me,
              I believe the ability to handle the high amperage is a quality of the tungsten itself more so than the tip flat diameter. Both the Tri-Mix and the Cryo-T are sort of the rugged workhorses of the electrodes out there....
              Carmen Electrode (Arc-Zone.com)
              CarmenElectrode.com

              powered by... Arc-Zone.com (R) Inc.

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              • #8
                I tried their Tri-Mix tonight... 3/32" with the long taper and very small flat, as prepared by DG. 220A, A/C, 65% balance, 150Hz. The tip bent and fell off the electrode before I even got a puddle formed. Maybe it can handle being that pointed with DC, but with A/C it was a joke. I jumped back to the 2% lanthanated with about a .035" - .040" flat and that worked ok... still seems like the tungsten is "eroding" fairly quickly though. I have it set to 220A, but I'm probably only 75% of the way down on the pedal once the puddle forms and I start moving. ??? Is it the 65% balance that's putting too much heat in the electrode?

                Comment


                • #9
                  2JZfan,

                  The 65% balance will put added heat into the electrode over a higher EN balance. However, 65%EN at 220 amps should not degrade a 2% lanthanated 3/32" electrode so quickly with 100% argon shielding gas or even a 50/50 He/Ar mix. I have run the same electrode from Diamond Ground Products with a 30 degree taper and a .020" flat at 250 amps plus.

                  It sounds to me like your arc start parameters may be set for too long of start time or too high of a start amperage. If this is the case a very "hot" start will erode the electrode quickly. Either change your start parameters or increase to a 1/8" electrode diameter.

                  The machine manual accurately describes how to reset the machine to factory defaults as well as manually enter start parameters. I use a hot start paramter of 50ms, 50 amps, and EP for my "hot" starts for 1/4" anodized with UHP+ helium. This much heat input requires a 5/32" elelctrode to prevent tungsten erosion.

                  By the way the tri-mix is basically for DC welding. The cryo-t I have not used. I pretty much stick with the 2% lanthanated for most work. I do prefer the tri-mix for stainless steel as there is a bit cleaner arc with less tendency to wander with a super fine point.

                  I am using the same power source: D300DX.

                  I hope this helps

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                  • #10
                    Thanks for the reply HAWK, I'll try reseting the machine on the odd chance that it had those parameters fiddled with at the factory (I know I haven't done it). You listed your configuration for the 1/4" Al with UHP helium, but for "normal" aluminum tasks with Argon, have you found that the factory settings are just fine? I have no intuition for what is too much or too little when it comes to time and amperage on a start.

                    I'll try to take a close-up picture of my tungsten too so that you guys can verify that it is in fact erosion and not contamination or something else.

                    Thanks as always!
                    Jeff

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                    • #11
                      2JZfan,

                      The factory defaults will work very well in most cases. The machine is set up to most closley match a 3/32" diameter tungsten. I purchased my machine used and learned the hard way. All four AC and DC programs were manually set up for specific applications. I learned the hard way.

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