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Handwheel Backlash

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  • cqer01 <jsm@gulfislands.com>
    I recently dropped into the local Busy Bee Tools, a Canadian supplier of offshore tools / machines. They sell the ubiquitous 7x10 (white - Moby Dick )
    Message 1 of 7 , Jan 21, 2003
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      I recently dropped into the local Busy Bee Tools, a Canadian supplier
      of offshore tools / machines. They sell the ubiquitous 7x10 (white -
      'Moby Dick') minilathe and I wanted to see one in person before
      laying out the cash. I was very disappointented with what I saw. All
      of the handwheel controls suffered pretty severe backlash (some over
      1/2 a turn). I am wondering if this is fairly normal on these
      machines and is one of the many "fixes" required or is this fairly
      uncommon on the 7x machines?

      Steve
    • Brian Drummond
      ... Look carefully at the backlash and work out where it is occurring. You may find that most of it is the leadscrew moving in/out and not slack in the nut. If
      Message 2 of 7 , Jan 22, 2003
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        On Wed, 22 Jan 2003 01:13:10 -0000, you wrote:

        >I recently dropped into the local Busy Bee Tools, a Canadian supplier
        >of offshore tools / machines. They sell the ubiquitous 7x10 (white -
        > 'Moby Dick') minilathe and I wanted to see one in person before
        >laying out the cash. I was very disappointented with what I saw. All
        >of the handwheel controls suffered pretty severe backlash (some over
        >1/2 a turn).

        Look carefully at the backlash and work out where it is occurring.
        You may find that most of it is the leadscrew moving in/out and not
        slack in the nut. If so, it can usually be eliminated by adjusting the
        leadscrew bearing endplay - often this is controlled by the handwheel
        itself (which probably screws onto the leadscrew and is held by a
        locknut). In other words if you see the handwheel moving in/out as you
        wind it through the backlash, that is not a problem.

        Adjust until just short of the handwheel binding, and if you still have
        more than 6-8 thou backlash, THEN I'd call it a problem.

        (If the 7x10s are different from this, which applies to lathes I have
        from 1910 to 2000(Unimat 3) then I apologise.)

        - Brian

        - Brian
      • vinceinwaukesha <vlm@debian.org>
        ... supplier All ... over ... This is hard to explain, but when you take it apart and see it, you ll understand it... Look at the top of the carriage. There
        Message 3 of 7 , Jan 22, 2003
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          --- In mlathemods@yahoogroups.com, "cqer01 <jsm@g...>" <jsm@g...>
          wrote:
          > I recently dropped into the local Busy Bee Tools, a Canadian
          supplier
          All
          > of the handwheel controls suffered pretty severe backlash (some
          over
          > 1/2 a turn). I am wondering if this is fairly normal on these
          > machines and is one of the many "fixes" required or is this fairly
          > uncommon on the 7x machines?

          This is hard to explain, but when you take it apart and see it,
          you'll understand it...

          Look at the top of the carriage. There are 3 allen wrench setscrews
          going into a nut below the carriage. The screw feeds into a nut
          underneath/inside the carriage.

          Adjust those three allen head screws so as to "twist" the nut against
          the screw to eliminate backlash. Obviously the "tighter" you make
          the screw the more wear there will be so there is some tradeoff,
          don't crank it all the way down without a good reason.

          I adjusted my harbor freight big red lathe from "about half a turn",
          as you say, to only a couple thousandths.

          I'm sure those adjustment screws vibrate loose during shipping, so
          the further you are from China the more backlash will be exhibited.
        • roylowenthal <roylowenthal@yahoo.com>
          After all the backlash mods/adjustments are done, there will still be some backlash on any real world feedscrews. The classic way to deal with it is to back
          Message 4 of 7 , Jan 22, 2003
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            After all the backlash mods/adjustments are done, there will still
            be some backlash on any real world feedscrews. The classic way to
            deal with it is to back off farther than needed, then advance to the
            desired position. As long as the backlash is taken out before the
            final positon is reached, it's irrelevant.

            Roy
            --- In mlathemods@yahoogroups.com, "cqer01 <jsm@g...>" <jsm@g...>
            wrote:
            > I recently dropped into the local Busy Bee Tools, a Canadian
            supplier
            > of offshore tools / machines. They sell the ubiquitous 7x10 (white -
            > 'Moby Dick') minilathe and I wanted to see one in person before
            > laying out the cash. I was very disappointented with what I saw.
            All
            > of the handwheel controls suffered pretty severe backlash (some
            over
            > 1/2 a turn). I am wondering if this is fairly normal on these
            > machines and is one of the many "fixes" required or is this fairly
            > uncommon on the 7x machines?
            >
            > Steve
          • cqer01 <jsm@gulfislands.com>
            Thanks for the information regarding the handwheel backlash. Unfortunately it sounds like this is a fairly typical problem in the 7X machines. Steve
            Message 5 of 7 , Jan 22, 2003
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              Thanks for the information regarding the handwheel backlash.
              Unfortunately it sounds like this is a fairly typical problem in the
              7X machines.

              Steve
            • JS. EARLY
              Steve It is a common problem with all lathes unless you get a Hardinge HLV and you would probably think they have to much. JWE Long Beach, CA ... From:
              Message 6 of 7 , Jan 23, 2003
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                Steve
                It is a common problem with all lathes unless you get a Hardinge HLV and you
                would probably think they have to much.
                JWE
                Long Beach, CA

                ----- Original Message -----
                From: <jsm@...>
                To: <mlathemods@yahoogroups.com>
                Sent: Wednesday, January 22, 2003 10:51 PM
                Subject: [mlathemods] Re: Handwheel Backlash


                > Thanks for the information regarding the handwheel backlash.
                > Unfortunately it sounds like this is a fairly typical problem in the
                > 7X machines.
                >
                > Steve
              • silectric@aol.com
                You could always fit a recirculating ball lead screw. Probably cost more than the lathe, but would eliminate perceptible back lash. [Non-text portions of this
                Message 7 of 7 , Jan 23, 2003
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                  You could always fit a recirculating ball lead screw. Probably cost more than
                  the lathe, but would eliminate perceptible back lash.


                  [Non-text portions of this message have been removed]
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