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Re: [SherlineCNC] CNC Lathe Question - Backlash how is everyone compensating for it?

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  • KM6VV
    Hi Joe, Work on the lathe is a little different from the mill, most all cuts are in the same direction, and backlash will be ran out in normal use. For CNC,
    Message 1 of 4 , Nov 5, 2005
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      Hi Joe,

      Work on the lathe is a little different from the mill, most all cuts are in the
      same direction, and backlash will be "ran out" in normal use. For CNC, as long
      as each cut is approached (after a retract) for some minimal distance, the
      backlash is out, just like in manual operation (my observations, can others
      confirm?).

      But yeah, an additional nut that could be spring loaded against the carriage nut
      would help.

      Alan KM6VV


      joecomunale1 wrote:

      > Backlash:
      > As Dave Hylands stated - that you could just tweak the G-code, and
      > approach the part in a way that removes the backlash.
      >
      > Has anyone found a good way to "eliminate" backlash?
      > I chose the Sherline Mill for this reason - as it has anti-backlash
      > adjustments. But - the Lathe does not have anti-backlash adjustments!!
      >
      > I did order the anti-backlash for the Z-axis of the lathe. But
      > Sherline doesn't seem to make anything for the X-axis.
      >
      > Maybe some kind of brass nut, with a slit, and compressed slightly?
      > Maybe some kind of delrin nut?
      >
      > Any advice?
      >
    • jeff briggs
      I used some brass tubing to punch out some washers from .030 polyethelyne, and I sandwiched those between the Sherline anti-backlash star nuts and where they
      Message 2 of 4 , Nov 5, 2005
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        I used some brass tubing to punch out some washers
        from .030" polyethelyne, and I sandwiched those
        between the Sherline anti-backlash star nuts and where
        they face against. This cut my backlash down on the X
        to .0005", on the Y to .00075" and the Z to .0015. I
        can live with that. I am using DeskCNC and IMService
        servo system, which seems to be able to handle that
        well. I get excellent repeatability with my setup.

        Jeff Briggs
        Briggs Models

        --- montanaaardvark <boblombardi@...> wrote:

        > --- In SherlineCNC@yahoogroups.com, "joecomunale1"
        > <joecomunale@c...> wrote:
        > >
        > > Backlash:
        > > As Dave Hylands stated - that you could just tweak
        > the G-code, and
        > > approach the part in a way that removes the
        > backlash.
        > >
        > > Has anyone found a good way to "eliminate"
        > backlash?
        > > I chose the Sherline Mill for this reason - as it
        > has anti-
        > backlash
        > > adjustments. But - the Lathe does not have
        > anti-backlash
        > adjustments!!
        > >
        > > I did order the anti-backlash for the Z-axis of
        > the lathe. But
        > > Sherline doesn't seem to make anything for the
        > X-axis.
        > >
        > > Maybe some kind of brass nut, with a slit, and
        > compressed slightly?
        > > Maybe some kind of delrin nut?
        > >
        > > Any advice?
        > >
        >
        > Not on a lathe but on a mill, I measure the backlash
        > with a dial
        > indicator and then enter that value into TurboCNC to
        > compensate
        > backlash. I thought most CNC controllers had a
        > backlash
        > compensation.
        >
        > I can make a few hundred 'back and forths' during a
        > part and not
        > have it creep out.
        >
        > Actually, my all time favorite quote, from years of
        > reading these
        > Sherline groups was, "your machine has backlash.
        > Get over it".
        > Meaning all machines have backlash, our job is to
        > learn how make
        > accurate parts despite that.
        >
        >
        >
        > Hope this helps,
        > Bob
        > Montana_Aardvark
        >
        >
        >
        >
        >
        >
        >
        >


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