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100% solid carbide boring bars?

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  • 100% solid carbide boring bars?

    Does anyone make an actual 1 piece solid carbide boring bar.If not why not ,it is 2017 now.I have used many of the 2 piece silver soldered so called solid carbide bars. They are only marginaly better than solid steel bars,Edwin Dirnbeck

  • #2
    Originally posted by Edwin Dirnbeck View Post
    Does anyone make an actual 1 piece solid carbide boring bar.If not why not ,it is 2017 now.I have used many of the 2 piece silver soldered so called solid carbide bars. They are only marginaly better than solid steel bars,Edwin Dirnbeck
    Plentifull.but they are so solid that there is no insert to change

    What is the problem with 2-piece boring bars that you would solve with single piece design?
    Insert pocket deformation in use?
    Location: Helsinki, Finland, Europe

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    • #3
      Originally posted by MattiJ View Post
      Plentifull.but they are so solid that there is no insert to change

      What is the problem with 2-piece boring bars that you would solve with single piece design?
      Insert pocket deformation in use?
      If you look at a 3/8 shank 2 piece bar The first 3/4 inch is steel and silver solder joint.So if your hole is 1 1/4 deep you would actuall be better of using a steel bar.And yes, pocket deformation. Edwin Dirnbeck

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      • #4
        I see. Bigger sizes than 3/8" work out to more favourable dimensions. And Im guessing that manufacturers are aiming the solid carbide boring bars for longer stickout ratios than 1:3.
        Location: Helsinki, Finland, Europe

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        • #5
          Originally posted by Edwin Dirnbeck View Post
          If you look at a 3/8 shank 2 piece bar The first 3/4 inch is steel and silver solder joint.So if your hole is 1 1/4 deep you would actuall be better of using a steel bar.And yes, pocket deformation. Edwin Dirnbeck
          The weight and rigidity of the carbide section affects deflection of anything behind the head and the resonant frequency of the whole bar so even if your hole was 3/4 of an inch deep there would be an advantage in carbide.
          If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

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          • #6
            Originally posted by Magicniner View Post
            The weight and rigidity of the carbide section affects deflection of anything behind the head and the resonant frequency of the whole bar so even if your hole was 3/4 of an inch deep there would be an advantage in carbide.
            I have many years of actually using these bars in real life. Yes, There are many places that they must be used,no argument.You are assuming that the steel portion is ridgidly bonded to the carbide this is not so,The joint is ALLWAYS THE WEAK SPOT.This is magnified in situations where you cant use coolant ,and the bar is down in the hole surrounded with hot chips .And yes ,pocket deformationis allways happens ,because the steel is made from a low temp tool steel that does not have much strength after silver soldering.The original 2 piece bars came out about 30 years ago..My thought is why not make them better. Edwin Dirnbeck
            Last edited by Edwin Dirnbeck; 04-25-2017, 09:19 AM.

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            • #7
              Originally posted by Edwin Dirnbeck View Post
              I have many years of actually using these bars in real life.
              Ditto, mainly ISCAR, some other major brands, on Stainless, Titanium, Tool Steels etc. and I've never seen any evidence of deformation or lack of rigidity.
              I think the less brittle tip is to prevent the bar exploding when it's inappropriately deployed ;-)
              If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

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              • #8
                Making the insert pocket shouldnt be impossible but threading the M2.5 hole would be interesting. Silver soldered HSS thread insert ?

                Other than manufacturing problems maybe the 2-part construction is beneficial by increasing the natural vibration frequency(less mass on the end of the spring) or maybe it has better vibration dampening properties.
                Location: Helsinki, Finland, Europe

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                • #9
                  Originally posted by MattiJ View Post
                  Making the insert pocket shouldnt be impossible but threading the M2.5 hole would be interesting.
                  EDM
                  If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

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                  • #10
                    Originally posted by Magicniner View Post
                    EDM
                    Still not fun or productive. If I remember correctly EDM cutting carbide is super slow and you wear more electrode than workpiece.
                    Location: Helsinki, Finland, Europe

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                    • #11
                      Or there's the possibility that since Tungsten Carbide parts are press formed from powder then sintered, and that dimensional change is very predictable, that process can be used to produce fine detail well enough to produce a usable thread?
                      If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

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                      • #12
                        I've been using solid carbide indexable bars from Mari - no complaints from me! MARITOOL

                        Cheers,

                        Frank Ford
                        HomeShopTech

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                        • #13
                          I'm sure that the likes of Sandvik, Kennametal, etc are researching ways of producing reliable one piece carbide boring bars, the emphasis being on reliable.

                          So far, I haven't tried out either bar. A slight problem with round barstock is not being able to put flats on it to fix the tip angle and height.
                          Having only a four way toolpost on the S & B, milled blocks are being made to hold the bar centre line directly under the tool clamping screws.
                          A 7mm slot in the block holds the small bar at the correct height when the tip angle of dip is ok. A cover plate about 4mm thick held on the block with three screws enables the boring bar height to be set after choosing the length of extension. The cover plate also spreads the toolpost clamping forces. A height gauge will be made.
                          The 12 mm boring bar will have an improved seating in it's block as we have a 12mm bullnosed end mill, but no 7mm one.

                          The second part of this post was puti n this thread by mistake, I meant it for my thread "home made solid carbide boring bars".
                          Last edited by old mart; 04-25-2017, 01:03 PM.

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                          • #14
                            Originally posted by MattiJ View Post
                            Still not fun or productive. If I remember correctly EDM cutting carbide is super slow and you wear more electrode than workpiece.
                            With a modern (past -95) machine the electrode wear on carbide is pretty "normal", as in the generators and technologies they use are much more sophisticated and can cut carbides efficiently. The electrodes though usually are wolfram copper, plain copper and graphites do not handle it so well.
                            Amount of experience is in direct proportion to the value of broken equipment.

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                            • #15
                              It will be done

                              Originally posted by MattiJ View Post
                              Making the insert pocket shouldnt be impossible but threading the M2.5 hole would be interesting. Silver soldered HSS thread insert ?

                              Other than manufacturing problems maybe the 2-part construction is beneficial by increasing the natural vibration frequency(less mass on the end of the spring) or maybe it has better vibration dampening properties.
                              Sixty years ago or so I ran one of the first ELOX edm machines in St Louis. The first attachment we bought was a rather crude tapping head that screwed an electrode into the solid carbide die sections that we were making.As for viabration , no one would ever purposely design a multiple piece cutting tool to prevent viabration.YesYES I know about the hollow bars filled with majik stuf .I have been suckered by them myself,they are Usless.Edwin Dirnbeckt

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