tool movement from right to left, then left to right, what happened?
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  1. #1
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    Default tool movement from right to left, then left to right, what happened?

    Put a 1/2" bar in the collet and take a light cut going from left to right. Carriage or compound.
    Now go back the other way. Slight hills get lopped off as seen with magnification.
    The movement is slow on both passes. Sharp centered brazed carbide C5 on 304 SS for example.
    I would think if the travel was fast then there would be a cross hatch pattern. But not slow with a radius on the tool.

    Why does the back travel hit material?

    I also remember a tidbit about depth of cut. Should be at least .005 or greater. Sorry to the author of that rule. I often have to dial in a dimension
    with .001 increments. Bad/good?

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    If I’m reading your thread correctly, you are experiencing spring in your part. It will always be there. You may also be dealing with a certain amount of spring in your machine tool holder.

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    Quote Originally Posted by rons View Post
    Slight hills get lopped off as seen with magnification.
    How much magnification ?

    It's a lathe, the cut will always be a helix with the feedrate as the distance between crests. Cutting left-to-right it will be a left hand helix, right to left the opposite.

    Try putting a totally flat-faced tool like a parting tool in the holder and do left-right right-left and see what you get.

    Or grind it ! (This is why hard turning sucks )

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    Quote Originally Posted by Spruewell View Post
    If I’m reading your thread correctly, you are experiencing spring in your part. It will always be there. You may also be dealing with a certain amount of spring in your machine tool holder.
    Spring when cutting .001 to .005 on some soft 304 SS?

    I think I need to get new belts. The instructions say to run through the entire speed range. I never do that. I rarely use high speed position.
    So if there is a set in the belts, can the positioning be altered to lower vibration. I mean positioning the two belt set elongations at 90 degrees?

    There is a vibration between 500 and 750 rpm. If I trust the little window readout on the machine.
    When I run a rpm on high speed and switch to low speed mode with the same rpm, the high speed mode rpm always appears to be greater.

    I'm all setup for using coolant but never tried it.

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    Quote Originally Posted by rons View Post
    ......
    Now go back the other way. Slight hills get lopped off as seen with magnification.
    As they should if all is good.


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