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Re: [atlas_craftsman] Re: piston type / wedge type ?

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  • Jon Elson
    ... I read how to do this in the book machine tool reconditioning by Edward F. Connelly. This is the thing he is selling for $92.50 I think in the back of
    Message 1 of 11 , Apr 1 11:25 PM
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      Steve Forslind wrote:

      >Sheeeesh! Sheldon is bigger; Sheldon is heavier, Sheldon is tougher,
      >Sheldon is is better.... I feel so inferior... ;->
      >
      >--- In atlas_craftsman@yahoogroups.com, Jon Elson <elson@p...> wrote:
      >
      >
      >>I have a 15" Sheldon lathe, now, and I do think the greater
      >>gripping power of the wedge design could make a difference on this
      >>machine, as it is capable of MUCH heavier cutting, and is vastly more
      >>rigid that the Atlas. (The tailstock on the Sheldon weighs as much
      >>
      >>
      >as the ENTIRE 12" Atlas machine!)
      >
      >
      >>Jon
      >>
      >>
      >
      >You're right, Jon; I think I'll do the dovetails myself.
      >
      >
      I read how to do this in the book "machine tool reconditioning" by Edward
      F. Connelly. This is the thing he is selling for $92.50 I think in the
      back of
      Home Shop Machinist. A bit high, but a really good book with an amazing
      amount of neat tricks to make tough stuff easy.

      Jon
    • Chris Herzog
      ... All the advice I got was that a wedge was superior just as Jon mentioned but a piston would be fine on a machine the size of the Atlas. The piston models
      Message 2 of 11 , Apr 2 9:12 AM
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        Jon Elson wrote:

        > mark67chevelle509 wrote:
        >
        >
        >>When describing quick change tool posts, what exactly is the
        >>difference between piston and wedge ?
        >>
        >>
        >
        > Both have dovetails. The piston type has a plunger that forces the
        > holder out from the dovetail, causing the tapered sides of the
        > dovetail to grip against the post.
        >
        > The wedge has a tapered gib that actually PULLS the holder tighter
        > in against the post, as well as exerting a lot of outward force against
        > the tapered sides of the holder. There's no question it holds the tool
        > holder more securely.
        >
        > I used a piston-type post with my 12" Atlas, and I think it was plenty
        > secure. I have a 15" Sheldon lathe, now, and I do think the greater
        > gripping power of the wedge design could make a difference on this
        > machine, as it is capable of MUCH heavier cutting, and is vastly more
        > rigid that the Atlas. (The tailstock on the Sheldon weighs as much as the
        > ENTIRE 12" Atlas machine!)

        All the advice I got was that a wedge was superior just as Jon mentioned
        but a piston would be fine on a machine the size of the Atlas.

        The piston models tend to be much less expensive. I was going to go
        wedge (because it was "better") until Enco lowered the price on their
        Phase II AXA-sized piston post to $89.95 for the post and a complete set
        of folders (www.use-enco.com part #505-2253). I couldn't justify twice
        the price for a wedge (almost twice the price).

        At that price point there is really *no* reason to stick with a lantern
        style post and I haven't regretted it for a moment.

        You need to do a little grinding on the T-slot nut but it's not a big
        deal (it's really more of a "plate" and it's sized to fit a pretty good
        range of applications).

        You'll end up with something that is strong, repeatable, holds well, and
        makes your life a whole *lot* easier!




        --
        Chris Herzog Software Technologies Group, Inc.
        mailto:zog@... http://www.stg.com
        (708) 547-0110 x225 FAX (708) 547-0783
      • n8as1@aol.com
        In a message dated 4/2/2004 11:51:19 AM Central Standard Time, zog@stg.com ... agreed ...but dont dispose of the lantern post ...it is still valuable for
        Message 3 of 11 , Apr 2 2:19 PM
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          In a message dated 4/2/2004 11:51:19 AM Central Standard Time, zog@...
          writes:

          > At that price point there is really *no* reason to stick with a lantern
          > style post and I haven't regretted it for a moment.
          >

          agreed ...but dont dispose of the lantern post ...it is still valuable for
          certain reaches /jam up situations .........find many uses yet ....also learn
          how to grind a chipbreaker so there is back & side rake on hi speed bits
          ......the Q.C. precludes the built in back rake of the lantern toolpost holder .....&
          finessing to a tight tolerance/finish goes easier w/ HS..........also
          cheaper!.......these machines were not designed for high speed /high pressure
          carbide tooling .......u will have more residual spring left making finish cuts a
          pain w/ carbide....read that as .005 under , or putting on .010 & getting less
          , then adding more & getting the total after springing out , causing
          undersize parts .......

          best wishes
          docn8as

          best wishes
          docn8as


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