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Dangers of facing.

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  • Dangers of facing.

    Hi, Recently iv experianced a few dangerious events when facing far away from the chuck, ie the work bending and going crazy, Really ruins my day. usally happens when I go a bit too agressive trying to reduce the length of a peice, often to get the center drill mark out..
    Basicly im wondering how to go about reduceing the chance and danger of that when reduceing length of a peice, Should I turn the diamiter insted insted of facing multiple times? Or just take finer facing cuts at a more sane feed rate? Or should I take deep facing cuts but at a very low feed rate?
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

  • #2
    Use a 4 jaw chuck. If you are taking facing cuts you are putting a lot of side load on the work and a 3 jaw isn't good at handling a lot of side load. With a 4 jaw it has much better grip and if facing precise centering isn't required.
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    • #3
      Use a steady rest if the part will not fit into the chuck far enough! More than three times the diameter hanging out of the chuck may be pushing your luck in most cases.

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      • #4
        Don't face a long thin piece.

        Don't face a piece that isn't held very deeply in the chuck. With a bit of mechanical instinct, you can look at a setup and decide if it's a bad idea.

        If you DO have to face long work sticking out, use the steady as a support.
        1601

        Keep eye on ball.
        Hashim Khan

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        • #5
          Glen has it right. Use the steady rest.

          But even before that, make sure you get fairly close just by sawing to length. You should be within 0.1-0.2".

          Best,

          BW
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          • #6
            If the part is short face it, if its long turn the extra off.

            simple rules like that are easy. if its round it goes in the lathe if its flat and square it goes in a mill.

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            • #7
              i sort of work on 3 X diameter protruding for facing, you can go more but i found i enter the mess up zone above this with bars climbing over the top and suchlike, like to use the same roule of thumb for parting too.
              i dont think i do any real precision stuff anyway, it all seems to be rip an tear these days, surface finish comparison blocks replaced with a chesegrater!
              mark

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              • #8
                I was using a 4 jaw, my problem wasent the material leaveing the chuck jaws, it was it actualy bending -_-; One thing I made I had to hammer back straight on my bench after a screwup (thankfuly straightness wasent a requirement)
                Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                • #9
                  Long skinny work has to be supported. If not with a center then with a steady rest. Period.

                  If the work has to be faced on the end all the way to the center first see if the spindle will "swallow" it; that is slip inside the spindle so only a short bit extends beyond the jaws for facing. Otherwise a steady rest is your best friend.

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                  • #10
                    I guess I should get my steady rest off the shelf and clean/oil it and stick it on my lathe then. Its around here.. somewhere.
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      Originally posted by Black_Moons
                      I guess I should get my steady rest off the shelf and clean/oil it and stick it on my lathe then. Its around here.. somewhere.
                      Yup. All that stuff that's painted to match your machine has a function.

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                      • #12
                        Ah, that explains why I ended up taking off the splash guard then. Or maybe it was because it got in the way of taking off my cross slide..
                        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                        • #13
                          Keep in mind that the angle of the cutter edge to the work affects the cutting forces. If you have a cutting edge parallel to the axis and plunge it straight in, all the force is directed radially and perpendicular to the axis (i.e. tries to bend the rod out). If the cutting edge is at an angle, the forces are shared radially and axially (partially tries to push it into the chuck).

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                          • #14
                            ahh, so thats why facing requires much lighter cuts then turning.
                            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                            • #15
                              You will be lucky if you haven't yet sprung your chuck jaws by now. Bending metal clamped in them is a terrible thing to do. Do you have a "How To Run a Lathe" manual?

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