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3/16 brased carbide tips ?

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  • recycalem
    Hi, does anyone know if 3/16 carbide bits are available for a 6 lathe Thanks jim
    Message 1 of 5 , May 31, 2011
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      Hi, does anyone know if 3/16 carbide bits are available for a 6 " lathe Thanks jim
    • David Beierl
      ... I m certain I ve seen 3/8 somewhere, if that s what you mean. I use 3/8 holders with triangular inserts. However in my experience the 618 isn t actually
      Message 2 of 5 , Jun 1, 2011
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        At 11:49 PM 5/31/2011, recycalem wrote:
        >Hi, does anyone know if 3/16 carbide bits are available for a 6 "
        >lathe Thanks jim

        I'm certain I've seen 3/8 somewhere, if that's what you mean. I use
        3/8 holders with triangular inserts.

        However in my experience the 618 isn't actually well suited to
        carbide*, and the longer I work with it the more I use HSS.

        *i.e. not stiff enough. Carbide makes a great finish but except for
        a tiny range of diameters you can't run it fast enough to get there
        without chatter. And because the lathe is limber the edge is more
        likely to break as well. I've had better luck with breakage using
        the 3/8 inserts than with half-inch brazed-in tools.

        Yours,
        DAvid

        --
        David Beierl -- Providence RI USA
        Atlas 618 6"/3" lathe ca. 1941, shiny-new Taig mill.
      • recycalem
        Hi, and thanks for your response. By 3/16 I am refering to the size that the tool holder will accept, I use 1/4 inch braised tip tools on my 12 inch lathe and
        Message 3 of 5 , Jun 1, 2011
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          Hi, and thanks for your response. By 3/16 I am refering to the size that the tool holder will accept, I use 1/4 inch braised tip tools on my 12 inch lathe and has worked out very well. But I cant seem to find any 3/16 inch square tools with braised on tips to fit the 6inch tool holder. It is a atlas tool holder. Thanks Jim

          --- In atlas_craftsman@yahoogroups.com, David Beierl <dbeierl@...> wrote:
          >
          > At 11:49 PM 5/31/2011, recycalem wrote:
          > >Hi, does anyone know if 3/16 carbide bits are available for a 6 "
          > >lathe Thanks jim
          >
          > I'm certain I've seen 3/8 somewhere, if that's what you mean. I use
          > 3/8 holders with triangular inserts.
          >
          > However in my experience the 618 isn't actually well suited to
          > carbide*, and the longer I work with it the more I use HSS.
          >
          > *i.e. not stiff enough. Carbide makes a great finish but except for
          > a tiny range of diameters you can't run it fast enough to get there
          > without chatter. And because the lathe is limber the edge is more
          > likely to break as well. I've had better luck with breakage using
          > the 3/8 inserts than with half-inch brazed-in tools.
          >
          > Yours,
          > DAvid
          >
          > --
          > David Beierl -- Providence RI USA
          > Atlas 618 6"/3" lathe ca. 1941, shiny-new Taig mill.
          >
        • Charlie Gallo
          On 6/1/2011 David Beierl wrote: ... Gahhhhh OK - first, and foremost, almost all brazed carbide lathe tools are DULL when you get them, and they need to be
          Message 4 of 5 , Jun 1, 2011
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            On 6/1/2011 David Beierl wrote:

            ...snip...
            > However in my experience the 618 isn't actually well suited to
            > carbide*, and the longer I work with it the more I use HSS.

            > *i.e. not stiff enough. Carbide makes a great finish but except for
            > a tiny range of diameters you can't run it fast enough to get there
            > without chatter. ...snip...


            Gahhhhh

            OK - first, and foremost, almost all brazed carbide lathe tools are DULL when you get them, and they need to be ground in

            As for insert carbide tooling. The whole "the lathe isn't stiff enough" line of thought is hokum. Today, industry runs carbide inserts on the tip on LONG boring bars, and they are a HECK of a lot more flexible than even a 6" atlas lathe is. Holders that take TPG-22X are CHEAP, and if you go to inserts like the CCMT 22.5x size, they are 'upsharp' small, and you can get one holder that will both turn and face, plus boring bars that fit the same inserts

            I'll give you a hint how far carbide has come since I wrote my web page - I'm running BIG surplus negative rake holders on my lathe, with inserts that have molded chipbreakers so you get an effective positive insert. You CAN run these inserts slowly, IF you wish (you just don't get the benefits of carbide), plus you can run them REAL fast. Today you can get grades that run well in steel, and OK in Aluminum (the aluminum specific grades are amazing in aluminum)

            TALK to the carbide suppliers - I've NEVER had to lie to them - I've told them 'my annual insert budget is in the $100 range, as I'm a hobby shop, but can you help me'. I've NEVER had one turn me down for tech support, in fact, they seem to LIKE the challenge, as it makes them THINK

            A LOT of the breakthroughs in carbide tooling have come from 2 sources - it's a field where 'real' vs SciFi 'Nanotechnology' makes a HUGE difference - they have figured out how to get carbide particles a lot smaller, and therefore they can make the inserts both HARDER and TOUGHER at the SAME TIME (hint, most grades today meat BOTH the old C2 and C6 ratings at the same time). The second driver is things like 'swiss' lathes and the like. These are SMALL machines - often VERY small - on the order of 6" swing, 18 inch bed, but WAY stiffer and faster than what we have, but because of their size, and gang tooling requirements tend to use SMALL tool holders (3/8" and 1/2" shank) with SMALL inserts, with positive cutting geometries because workpiece diameters are small

            My slightly out of date page, but everything I've written there still holds true (just that today you have MORE choices) can be found at

            http://www.thegallos.com/carbide.htm

            Feedback is ALWAYS welcome, feel free to browse the site

            --
            73 de KG2V - Charles Gallo
            Quality Custom Machine-shop work for the radio amateur (sm)
          • David Beierl
            ... Thanks, Charlie, I ll study up on your stuff. Yours, David
            Message 5 of 5 , Jun 2, 2011
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              At 12:56 AM 6/2/2011, Charlie Gallo wrote:
              >Gahhhhh

              Thanks, Charlie, I'll study up on your stuff.

              Yours,
              David
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