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  1. #21
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    Thanks. The bottom of the tool post was anodized and very slippery.I ran it over a piece of emery cloth on a flat plate until I exposed the aluminum. I also made a "gasket" of sandpaper at the same surface and it cured the twisting. Thanks to you all.

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  3. #22
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    Quote Originally Posted by lucky7 View Post
    Have you checked the bottom of the toolpost is flat without burrs/crud? Is the top of the cross-slide flat also without burrs? Have you tried the old trick of paper between the toolpost and cross slide?

    If all that fails... I bought a Dickson toolpost years ago for my Colchester Chipmaster that had an extra hole at the edge of the block. Don’t know if the factory did that or prev owner, but was useful to spot a hole into my cross slide for a pin. No rotation :-)

    Lucky7
    Pretty sure that's Factory, as i have seen it on several variations of that type of post.

    For the OP, in order, check cleanliness, flatness, and tightness. If the parts are not clean, the mating surfaces flat, and all the hold down fastenings tight, you are pretty much doomed.

    And, don't talk about those particular machines here. Read the posted stickies about what machines are not welcome topics of discussion.

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  5. #23
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    All you need to do to solve the problem is to relieve the center 1/2 to 2/3 of the base of the tool post. Chuck it up in a 4-jaw and take off 5-10 thou leaving the outer portion of the base intact.. Now pressure will be applied at a distance from the center. Right now pressure is being applied near the mount bolt as the post deflects some with compression. I did this on my QCTP years ago and it makes a huge difference. I also wrote it up here. I’ll see if I can find it.

    This will work. Simple, quick, effective.
    Denis

    Added: machining a tee nut to fit lathe compound
    Last edited by dgfoster; 01-13-2020 at 07:38 PM. Reason: Typos

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  7. #24
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    While I was working at my lathe I took a picture of the base of my QCTP. I relieved the base probably 8 or ten years ago. I have not had a boit of problems with twisting since relieving the base.

    img_6280-1-.jpg


    img_6281-1-.jpg


    Denis

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  9. #25
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    Have you check to see if the top of your compound top is flat? Robin sells some really nice stones that you can use to clean up surfaces and make things are flat and square.

  10. #26
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    Hi Folks,

    While searching for info about my Emco super 11 I came across this youtube video of Stefan Gotteswinter doing the same thing (solid tool-post) on the Super 11.

    YouTube

    On my quick-change toolpost, there's a dowel hole on the underside - I suppose if you were daring, you could make a shallow dowel hole on the compound for your standard compound setup and add a dowel pin (would that be sacrilege?)

    BTW: New user to PM and pretty much a noob to metalwork (that bit i did messing around with an old P&W jeweler's lathe 40 years ago doesn't really count for mucn)


    Cheers,
    Dave



    Quote Originally Posted by EPAIII View Post
    Here is a link to that video:

    YouTube

    It is a great video about a great mount. He has a very good understanding of what is going on when a tool post is mounted.

  11. #27
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    Quote Originally Posted by bigwave View Post
    Hi Folks,

    On my quick-change toolpost, there's a dowel hole on the underside - I suppose if you were daring, you could make a shallow dowel hole on the compound for your standard compound setup and add a dowel pin (would that be sacrilege?)

    Cheers,
    Dave
    Not sacrilege, but also not necessary or particularly useful. Just relieve the bottom of the toolpost as above. Then do more if you find you (unlikely) need to. I find myself wanting to have my toolpost at a wide variety of angles to the bed depending on what tool I am using and what operation I am doing. Multifix toolposts have multiple fixing angles for the same reason. How many holes are you going to make?

    Denis

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  13. #28
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    Quote Originally Posted by dgfoster View Post
    Not sacrilege, but also not necessary or particularly useful. Just relieve the bottom of the toolpost as above. Then do more if you find you (unlikely) need to.

    Denis
    Relieving the center of the toolpost bottom is a great idea. The toolpost itself may have a lot of shape to the bottom- recently while scraping in a compound ,I found installing the tool post warped the compound way out of whack- then had to flatten the toolpost base and scrape the top surface of the compound to get it back to straight.
    I like the tee nut relief too.


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