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rotating ball screw ?

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  • Dave Mucha
    Hi all, I am starting to lay out a mini-mill retrofit and am thinking about using a fixed screw and a rotating ball nut. Anyone have plans ? ideas ? warnings ?
    Message 1 of 9 , Feb 1, 2008
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      Hi all,

      I am starting to lay out a mini-mill retrofit and am thinking about
      using a fixed screw and a rotating ball nut.

      Anyone have plans ? ideas ? warnings ?

      It seems the nut needs to be on a bearing block with thrust bearings.

      Thanks,

      Dave

      (cross posted on the CCED list)
    • Mike Nash
      Hi Dave, There have been threads/posts about this on CNCzone you could look up. But I m wondering where you would need this arrangement on the mini-mill? I
      Message 2 of 9 , Feb 1, 2008
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        Hi Dave,

        There have been threads/posts about this on CNCzone you could look up. But
        I'm wondering where you would need this arrangement on the mini-mill? I
        can't see anywhere it would fit except for maybe the Z axis. Also, are you
        going to change the balls to give a tighter fit, or use opposing ball nuts?

        I've got a mini that someone else converted (John Labutski) and I snagged it
        from him when health issues got in the way. One issue with the belt drive
        that bothers me is a cyclical positioning error. It's out 0.001" every half
        turn of the ballscrew. I finally realized it was due to the setscrews
        shifting the ballscrew pulley off axis slightly. This induces a position
        error, not to mention a tight/slack belt condition. I rebushed the pulley
        and it improved but did not get rid if the problem. It may be the pulley
        itself is not true as it's plastic type material. I plan to try it as direct
        drive.

        Mike Nash

        ----- Original Message -----
        From: "Dave Mucha"

        > Hi all,
        >
        > I am starting to lay out a mini-mill retrofit and am thinking about
        > using a fixed screw and a rotating ball nut.
        >
        > Anyone have plans ? ideas ? warnings ?
        >
        > It seems the nut needs to be on a bearing block with thrust bearings.
        >
        > Thanks,
        >
        > Dave
      • Dave Mucha
        I looked at the sites I could find and laid out an assembly I think I could build with my lathe and mill. It is a bit bigger than I would really like, but
        Message 3 of 9 , Feb 3, 2008
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          I looked at the sites I could find and laid out an assembly I think I
          could build with my lathe and mill.

          It is a bit bigger than I would really like, but sometimes oversized
          is better.

          Anyone want a look and offer comments ?

          Dave



          --- In GrizHFMinimill@yahoogroups.com, "Mike Nash" <mn.minimill@...>
          wrote:
          >
          > Hi Dave,
          >
          > There have been threads/posts about this on CNCzone you could look
          up. But
          > I'm wondering where you would need this arrangement on the mini-mill? I
          > can't see anywhere it would fit except for maybe the Z axis. Also,
          are you
          > going to change the balls to give a tighter fit, or use opposing
          ball nuts?
          >
          > I've got a mini that someone else converted (John Labutski) and I
          snagged it
          > from him when health issues got in the way. One issue with the belt
          drive
          > that bothers me is a cyclical positioning error. It's out 0.001"
          every half
          > turn of the ballscrew. I finally realized it was due to the setscrews
          > shifting the ballscrew pulley off axis slightly. This induces a
          position
          > error, not to mention a tight/slack belt condition. I rebushed the
          pulley
          > and it improved but did not get rid if the problem. It may be the
          pulley
          > itself is not true as it's plastic type material. I plan to try it
          as direct
          > drive.
          >
          > Mike Nash
          >
          > ----- Original Message -----
          > From: "Dave Mucha"
          >
          > > Hi all,
          > >
          > > I am starting to lay out a mini-mill retrofit and am thinking about
          > > using a fixed screw and a rotating ball nut.
          > >
          > > Anyone have plans ? ideas ? warnings ?
          > >
          > > It seems the nut needs to be on a bearing block with thrust bearings.
          > >
          > > Thanks,
          > >
          > > Dave
          >
        • Ray Livingston
          Dave, I ll take a look, if you can give me a DXF. Ain t got no 3D CAD. Regards, Ray L. ... I ... mill? I ... belt ... setscrews ... about ... bearings.
          Message 4 of 9 , Feb 3, 2008
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            Dave,

            I'll take a look, if you can give me a DXF. Ain't got no 3D CAD.

            Regards,
            Ray L.


            --- In GrizHFMinimill@yahoogroups.com, "Dave Mucha" <dave_mucha@...>
            wrote:
            >
            > I looked at the sites I could find and laid out an assembly I think
            I
            > could build with my lathe and mill.
            >
            > It is a bit bigger than I would really like, but sometimes oversized
            > is better.
            >
            > Anyone want a look and offer comments ?
            >
            > Dave
            >
            >
            >
            > --- In GrizHFMinimill@yahoogroups.com, "Mike Nash" <mn.minimill@>
            > wrote:
            > >
            > > Hi Dave,
            > >
            > > There have been threads/posts about this on CNCzone you could look
            > up. But
            > > I'm wondering where you would need this arrangement on the mini-
            mill? I
            > > can't see anywhere it would fit except for maybe the Z axis. Also,
            > are you
            > > going to change the balls to give a tighter fit, or use opposing
            > ball nuts?
            > >
            > > I've got a mini that someone else converted (John Labutski) and I
            > snagged it
            > > from him when health issues got in the way. One issue with the
            belt
            > drive
            > > that bothers me is a cyclical positioning error. It's out 0.001"
            > every half
            > > turn of the ballscrew. I finally realized it was due to the
            setscrews
            > > shifting the ballscrew pulley off axis slightly. This induces a
            > position
            > > error, not to mention a tight/slack belt condition. I rebushed the
            > pulley
            > > and it improved but did not get rid if the problem. It may be the
            > pulley
            > > itself is not true as it's plastic type material. I plan to try it
            > as direct
            > > drive.
            > >
            > > Mike Nash
            > >
            > > ----- Original Message -----
            > > From: "Dave Mucha"
            > >
            > > > Hi all,
            > > >
            > > > I am starting to lay out a mini-mill retrofit and am thinking
            about
            > > > using a fixed screw and a rotating ball nut.
            > > >
            > > > Anyone have plans ? ideas ? warnings ?
            > > >
            > > > It seems the nut needs to be on a bearing block with thrust
            bearings.
            > > >
            > > > Thanks,
            > > >
            > > > Dave
            > >
            >
          • Brian Pitt
            ... this ones free and can open or import many formats http://www.alibre.com/xpress/software/alibre-design-xpress.asp or you can get one that s just a viewer
            Message 5 of 9 , Feb 3, 2008
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              On Sunday 03 February 2008 15:23, Ray Livingston wrote:
              > I'll take a look, if you can give me a DXF. Ain't got no 3D CAD.
              > Regards,
              > Ray L.

              this ones free and can open or import many formats
              http://www.alibre.com/xpress/software/alibre-design-xpress.asp
              or you can get one that's just a viewer
              http://www.edrawingsviewer.com/pages/products/eDrawingsViewerpage.html

              Brian
              --
              "Nemo me impune lacesset"
            • Dave Mucha
              ... 2D on pdf files. easy for anyone to see. If they are clear, I ll drop them in the files section. Dave rooted for New England for the fact that they could
              Message 6 of 9 , Feb 3, 2008
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                --- In GrizHFMinimill@yahoogroups.com, "Ray Livingston"
                <jagboy1964@...> wrote:
                >
                > Dave,
                >
                > I'll take a look, if you can give me a DXF. Ain't got no 3D CAD.
                >
                > Regards,
                > Ray L.


                2D on pdf files. easy for anyone to see.

                If they are clear, I'll drop them in the files section.

                Dave

                rooted for New England for the fact that they could have made history
                as the 2nd perfect season.

                at least it was a good game.

                Dave
              • Barry Young
                Hi Dave: An idea, One which probably five people have already come up with but I catch up on all the email on Monday mornings in the order it was received. For
                Message 7 of 9 , Feb 4, 2008
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                  Hi Dave:

                  An idea, One which probably five people have already
                  come up with but I catch up on all the email on Monday
                  mornings in the order it was received. For the short
                  length of minimill screws, no gain is to be had by the
                  major PITA that is b uilding a rotating nut. Rotating
                  nuts are for long screws that tend to whip.

                  Barry


                  --- Dave Mucha <dave_mucha@...> wrote:

                  > Hi all,
                  >
                  > I am starting to lay out a mini-mill retrofit and am
                  > thinking about
                  > using a fixed screw and a rotating ball nut.
                  >
                  > Anyone have plans ? ideas ? warnings ?
                  >
                  > It seems the nut needs to be on a bearing block with
                  > thrust bearings.
                  >
                  > Thanks,
                  >
                  > Dave
                  >
                  > (cross posted on the CCED list)
                  >
                  >
                  >
                  >
                  > Yahoo! Groups Links
                  >
                  > (Yahoo! ID required)
                  >
                  > mailto:GrizHFMinimill-fullfeatured@yahoogroups.com
                  >
                  >
                  >



                  ____________________________________________________________________________________
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                • Barry Young
                  Hi Mike: I had a similar problem which I cured by using aluminum softjaws cut to grip the teeth of the pulley rather than the rim as it was bored. The rims are
                  Message 8 of 9 , Feb 4, 2008
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                    Hi Mike:

                    I had a similar problem which I cured by using
                    aluminum softjaws cut to grip the teeth of the pulley
                    rather than the rim as it was bored. The rims are not
                    concentric with the teeth.

                    Hope this helps.

                    Barry


                    --- Mike Nash <mn.minimill@...> wrote:

                    > Hi Dave,
                    >
                    > There have been threads/posts about this on CNCzone
                    > you could look up. But
                    > I'm wondering where you would need this arrangement
                    > on the mini-mill? I
                    > can't see anywhere it would fit except for maybe the
                    > Z axis. Also, are you
                    > going to change the balls to give a tighter fit, or
                    > use opposing ball nuts?
                    >
                    > I've got a mini that someone else converted (John
                    > Labutski) and I snagged it
                    > from him when health issues got in the way. One
                    > issue with the belt drive
                    > that bothers me is a cyclical positioning error.
                    > It's out 0.001" every half
                    > turn of the ballscrew. I finally realized it was due
                    > to the setscrews
                    > shifting the ballscrew pulley off axis slightly.
                    > This induces a position
                    > error, not to mention a tight/slack belt condition.
                    > I rebushed the pulley
                    > and it improved but did not get rid if the problem.
                    > It may be the pulley
                    > itself is not true as it's plastic type material. I
                    > plan to try it as direct
                    > drive.
                    >
                    > Mike Nash
                    >
                    > ----- Original Message -----
                    > From: "Dave Mucha"
                    >
                    > > Hi all,
                    > >
                    > > I am starting to lay out a mini-mill retrofit and
                    > am thinking about
                    > > using a fixed screw and a rotating ball nut.
                    > >
                    > > Anyone have plans ? ideas ? warnings ?
                    > >
                    > > It seems the nut needs to be on a bearing block
                    > with thrust bearings.
                    > >
                    > > Thanks,
                    > >
                    > > Dave
                    >
                    >
                    >
                    >
                    > Yahoo! Groups Links
                    >
                    > (Yahoo! ID required)
                    >
                    > mailto:GrizHFMinimill-fullfeatured@yahoogroups.com
                    >
                    >
                    >



                    ____________________________________________________________________________________
                    Looking for last minute shopping deals?
                    Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping
                  • Dave Mucha
                    ... I think I got it to the point it makes sense to someone other than myself. : ) I ll send it over tonite after work. Dave
                    Message 9 of 9 , Feb 4, 2008
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                      --- In GrizHFMinimill@yahoogroups.com, "Ray Livingston"
                      <jagboy1964@...> wrote:
                      >
                      > Dave,
                      >
                      > I'll take a look, if you can give me a DXF. Ain't got no 3D CAD.
                      >
                      > Regards,
                      > Ray L.

                      I think I got it to the point it makes sense to someone other than
                      myself. : )

                      I'll send it over tonite after work.

                      Dave
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