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RE: [SherlineCNC] X axis backlash problem

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  • KM6VV
    Hi Neil, Take a look at the exploded view of the mill. I believe you ll find a threaded piece (nut) UNDER the X ways (saddle). It should be secured with a
    Message 1 of 5 , Sep 11 9:04 AM
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      Hi Neil,

      Take a look at the exploded view of the mill. I believe you'll find a
      threaded piece (nut) UNDER the X ways (saddle). It should be secured with a
      setscrew if I remember correctly. Oops, I think you've already found it!

      Also check the nut that adds the loading to the bearing pair in the stepper
      motor mount. Although it shouldn't be the cause of the problem you are
      seeing, it's something to check while you're at it.

      Alan KM6VV


      > Behalf Of Neil Albert
      >
      > Please help. I have some critical project I need to complete and I'm
      > in a bind.
      >
      > I am having problems with my CNC equipped 2000 mill, where even after
      > replacing the X-axis backlash nut, the backlash nut will repeatedly
      > push out of its seat in the mill saddle during clockwise leadscrew
      > rotation, to the point where the backlash is about 1/2 turn or.025".
      >
      > Could I possibly need a new mill saddle? The nut is soft brass and the
      > saddle is Anodized aluminim which is much harder.
      >
      >
      > I am coming back to using my Sherline mill after having moved and not
      > used it for a couple of months I observed the problem and replaced the
      > backlash nut. The problem seemed to have been corrected but then
      > returned after a couple of hours use. Retightening the lock does not
      > fix the problem, However I did not replace the backlash lock.
      >
      >
      > Neil Albert
    • Neil Albert
      Alan, Thanks so much for reponding. I just got off the phone with Craig Libuse, and he pointed out that that there is a set screw holding the slide screw
      Message 2 of 5 , Sep 11 9:18 AM
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        Alan,
        Thanks so much for reponding. I just got off the phone with Craig
        Libuse, and he pointed out that that there is a set screw holding the
        "slide screw insert" which needs to have the saddle removed to obtain
        acesss to. Since I was able to remove the slide screw insert without
        loosening that set screw, you would seem to be right on-the-money.


        Thanks again, Alan.


        Neil
        --- In SherlineCNC@yahoogroups.com, "KM6VV" <KM6VV@...> wrote:
        >
        > Hi Neil,
        >
        > Take a look at the exploded view of the mill. I believe you'll find a
        > threaded piece (nut) UNDER the X ways (saddle). It should be
        secured with a
        > setscrew if I remember correctly. Oops, I think you've already
        found it!
        >
        > Also check the nut that adds the loading to the bearing pair in the
        stepper
        > motor mount. Although it shouldn't be the cause of the problem you are
        > seeing, it's something to check while you're at it.
        >
        > Alan KM6VV
        >
        >
        > > Behalf Of Neil Albert
        > >
        > > Please help. I have some critical project I need to complete and I'm
        > > in a bind.
        > >
        > > I am having problems with my CNC equipped 2000 mill, where even after
        > > replacing the X-axis backlash nut, the backlash nut will repeatedly
        > > push out of its seat in the mill saddle during clockwise leadscrew
        > > rotation, to the point where the backlash is about 1/2 turn or.025".
        > >
        > > Could I possibly need a new mill saddle? The nut is soft brass and the
        > > saddle is Anodized aluminim which is much harder.
        > >
        > >
        > > I am coming back to using my Sherline mill after having moved and not
        > > used it for a couple of months I observed the problem and replaced the
        > > backlash nut. The problem seemed to have been corrected but then
        > > returned after a couple of hours use. Retightening the lock does not
        > > fix the problem, However I did not replace the backlash lock.
        > >
        > >
        > > Neil Albert
        >
      • Carol & Jerry Jankura
        Hi, Neil: I m just guessing here, but I doubt that you need a new saddle. The antibacklash nut does not screw into the saddle. Its purpose is to provide an
        Message 3 of 5 , Sep 11 9:23 AM
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          Hi, Neil:

          I'm just guessing here, but I doubt that you need a new saddle. The
          antibacklash nut does not screw into the saddle. Its purpose is to provide
          an adjustment to try to "pull" the leadscrew from the threaded insert in the
          saddle. That way, the leadscrew always rides on the "front" side of the
          thread on the insert and on the "back" side of the thread on the
          antibacklash nut.

          I think it's coming loose because the star nut that's supposed to prevent it
          from rotating when the leadscrew is turned is not doing its job. Can you
          tighten the screw tha holds the star nut to the saddle? If not, the saddle
          thread may be bad.

          I'm thinking that the star nut that is supposed to prevent the antibacklash
          nut from turning is not doing its job. This might happen if the points on
          the star are munged up. You might try making a piece to replace that star
          nut. Think about a "U" with a large base that goes around the leadscrew.
          You'd put a hole in the fat base and use the same threaded hole that holds
          the star nut. I read about this just a few days ago. I think it was on
          Sherline's web site in the area that has all of those tips submitted by
          users.

          -- Jerry Jankura
          Strongsville, Ohio
          So many toys.... So little time....



          > Please help. I have some critical project I need to complete and I'm
          > in a bind.
          >
          > I am having problems with my CNC equipped 2000 mill, where even after
          > replacing the X-axis backlash nut, the backlash nut will repeatedly
          > push out of its seat in the mill saddle during clockwise leadscrew
          > rotation, to the point where the backlash is about 1/2 turn or.025".
          >
          > Could I possibly need a new mill saddle? The nut is soft brass and the
          > saddle is Anodized aluminim which is much harder.
          >
          >
          > I am coming back to using my Sherline mill after having moved and not
          > used it for a couple of months I observed the problem and replaced the
          > backlash nut. The problem seemed to have been corrected but then
          > returned after a couple of hours use. Retightening the lock does not
          > fix the problem, However I did not replace the backlash lock.
          >
          >
          >
          >
          > Neil Albert
          >
          >
          >
          >
          >
          >
          > Yahoo! Groups Links
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          >
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          >
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          >
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        • jehancocy
          You don t need a new saddle. just to review, there are two nuts, the leadscrew nut under the saddle held with a setscrew and the anti-backlash preload nut that
          Message 4 of 5 , Sep 11 9:36 AM
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            You don't need a new saddle.

            just to review, there are two nuts, the leadscrew nut under the
            saddle held with a setscrew and the anti-backlash preload nut that
            is visible on the leadscrew near the front of the saddle. I've had
            problems with the leadscrew nut coming loose. I used thread lock on
            it and it fixed the problem. When you need to get it out, use an
            old leadscrew or brass punch and tap it out. The setscrew can also
            be locked with thread lock. Heating the setscrew with a soldering
            iron will loosen the thread lock if you need to remove it.

            Take the leadscrew nut out from under the saddle and see if the
            setscrew is dragging along the nut. If so, lock with threadlock or
            super glue.

            If the anit-backlash nut is loose, there should be a star washer as
            mentioned that holds it in place. I've noticed some of the new
            leadscrews coming with a straight knurled anti-backlash nut. There
            must be a new mechanism to hold it.
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