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Re: [atlas_craftsman] RE;Vibration, belt tenison Atlas 10"

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  • Jon Elson
    ... There is supposed to be a spring on that bolt. ... Yup, this is not uncommon. What happens is the setscrew gets loose, and then the Zamak pulley works
    Message 1 of 7 , Mar 31, 2002
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      chris111148198 wrote:

      > Hi Every one.I was wondering if any body knew how the belt tenision
      > between the motor and the counter shaft was sus posed to be
      > adjusted. . I noticed that there was a boss on the motor base with a
      > elongated hole in it. and a corrosponding hole in line on the counter
      > shaft bracket ( this hole is clearenced for a 3-8 bolt).I just do not
      > understand how a bolt is susposed to be employed. (unless i'am
      > missing parts ,

      There is supposed to be a spring on that bolt.

      > The parts book shows a slightly different base in
      > that it does not have the boss with its elongated hole) I forgot to
      > mention that this is a Atlas 10-th42 Horizontal counter shaft,
      > I have read all the postings on chatter and vibration and i have
      > segmented belts, I"am gettig 20 thou runout on the large counter
      > shaft pulley, dont't know if this is my problem or not . It looks
      > like the 3-4 bore is slightly wallowed out.

      Yup, this is not uncommon. What happens is the setscrew gets loose, and
      then the Zamak pulley works against the steel shaft, and the steel wins
      every time. the fix is to bore out the pulley and then fit a steel hub
      insert
      into it. But, it is not so easy to do when the lathe is down.

      Jon
    • chris111148198
      ... tenision ... with a ... counter ... not ... to ... have ... loose, and ... wins ... hub ... Hi Jon: Well, thank you very much for the info on the spring.
      Message 2 of 7 , Apr 1, 2002
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        --- In atlas_craftsman@y..., Jon Elson <elson@p...> wrote:
        > chris111148198 wrote:
        >
        > > Hi Every one.I was wondering if any body knew how the belt
        tenision
        > > between the motor and the counter shaft was sus posed to be
        > > adjusted. . I noticed that there was a boss on the motor base
        with a
        > > elongated hole in it. and a corrosponding hole in line on the
        counter
        > > shaft bracket ( this hole is clearenced for a 3-8 bolt).I just do
        not
        > > understand how a bolt is susposed to be employed. (unless i'am
        > > missing parts ,
        >
        > There is supposed to be a spring on that bolt.
        >
        > > The parts book shows a slightly different base in
        > > that it does not have the boss with its elongated hole) I forgot
        to



        > > mention that this is a Atlas 10-th42 Horizontal counter shaft,
        > > I have read all the postings on chatter and vibration and i
        have
        > > segmented belts, I"am gettig 20 thou runout on the large counter
        > > shaft pulley, dont't know if this is my problem or not . It looks
        > > like the 3-4 bore is slightly wallowed out.
        >
        > Yup, this is not uncommon. What happens is the setscrew gets
        loose, and
        > then the Zamak pulley works against the steel shaft, and the steel
        wins
        > every time. the fix is to bore out the pulley and then fit a steel
        hub
        > insert
        > into it. But, it is not so easy to do when the lathe is down.
        >
        > Jon



        Hi Jon: Well, thank you very much for the info on the
        spring. I was wondering if i have the wrong motor base plate for my
        th-42 (10") As i said it is not pictured in the break down.( Two
        different ones are shown for the horizontal and the Vertical counter
        shaft) But I guess it really dosen't matter as long as the lathe
        runs ( smoothly) This Rock and roll has been driving me nuts . There
        was a article in HSM on making a balancing stand , that would be
        handy , it seems that everything is designed marginal on these Atlas
        lathes , so everything has to be right up to spec.
        Would that spring have to be very strong?
        By the way what is this Zamak Metal , Can Zamak be
        annealed?Is it brittle ? Need to correct minor bend on pulley. I
        heard that they made all the gears out of it ,. Why use it for a
        pulley?
        I'am not sure how I would bore this pulley , it seems that
        boring it on the mill would be better, What do you think of recutting
        the grooves after it is bored and bushed? and then balance.

        Thanks for all the help Chris Miller
      • PIHPGS@aol.com
        Hi your v-belt should be just tight enough so that it will not slip under load. a belt that is too tight will overload the bearings and the motor. hope it
        Message 3 of 7 , Apr 1, 2002
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          Hi
          your v-belt should be just tight enough so that it will not slip under load.

          a belt that is too tight will overload the bearings and the motor.

          hope it helps

          chuck
        • Jon Elson
          ... I don t think so. Mostly, the weight of the motor does the job, it just needs a little more tension on the belt. If the whole countershaft assembly is
          Message 4 of 7 , Apr 1, 2002
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            chris111148198 wrote:

            > --- In atlas_craftsman@y..., Jon Elson <elson@p...> wrote:
            > > chris111148198 wrote:
            > >
            > > > Hi Every one.I was wondering if any body knew how the belt
            > tenision
            > > > between the motor and the counter shaft was sus posed to be
            > > > adjusted. . I noticed that there was a boss on the motor base
            > with a
            > > > elongated hole in it. and a corrosponding hole in line on the
            > counter
            > > > shaft bracket ( this hole is clearenced for a 3-8 bolt).I just do
            > not
            > > > understand how a bolt is susposed to be employed. (unless i'am
            > > > missing parts ,
            > >
            > > There is supposed to be a spring on that bolt.
            > >
            > > > The parts book shows a slightly different base in
            > > > that it does not have the boss with its elongated hole) I forgot
            > to
            >
            >
            >
            > > > mention that this is a Atlas 10-th42 Horizontal counter shaft,
            > > > I have read all the postings on chatter and vibration and i
            > have
            > > > segmented belts, I"am gettig 20 thou runout on the large counter
            > > > shaft pulley, dont't know if this is my problem or not . It looks
            > > > like the 3-4 bore is slightly wallowed out.
            > >
            > > Yup, this is not uncommon. What happens is the setscrew gets
            > loose, and
            > > then the Zamak pulley works against the steel shaft, and the steel
            > wins
            > > every time. the fix is to bore out the pulley and then fit a steel
            > hub
            > > insert
            > > into it. But, it is not so easy to do when the lathe is down.
            > >
            > > Jon
            >
            > Hi Jon: Well, thank you very much for the info on the
            > spring. I was wondering if i have the wrong motor base plate for my
            > th-42 (10") As i said it is not pictured in the break down.( Two
            > different ones are shown for the horizontal and the Vertical counter
            > shaft) But I guess it really dosen't matter as long as the lathe
            > runs ( smoothly) This Rock and roll has been driving me nuts . There
            > was a article in HSM on making a balancing stand , that would be
            > handy , it seems that everything is designed marginal on these Atlas
            > lathes , so everything has to be right up to spec.
            > Would that spring have to be very strong?

            I don't think so. Mostly, the weight of the motor does the job,
            it just needs a little more tension on the belt. If the whole
            countershaft assembly is wobbling, the belt won't be able to give a
            steady pull.

            > By the way what is this Zamak Metal , Can Zamak be
            > annealed?

            No, it is a Zinc die-casting alloy.

            > Is it brittle ?

            Yes, just like old carburetors and such, very brittle.

            > Need to correct minor bend on pulley. I
            > heard that they made all the gears out of it ,. Why use it for a
            > pulley?

            It's cheap, they own a license for the alloy, they have big casting presses
            for the stuff, they make as much of the lathe out of it as possible.

            >
            > I'am not sure how I would bore this pulley , it seems that
            > boring it on the mill would be better, What do you think of recutting
            > the grooves after it is bored and bushed? and then balance.

            Yes, if you have a mill, that would be fine. Why not align the pulley
            grooves to the table (and spindle) and then bore in line with that.
            Then, when you mount the pulley on the new hub, it should run
            true. You could make the hub insert before disassembling the lathe.

            Jon
          • Gary Lair
            My machine has a quick release screw that bears on a barrel nut that slips into the oval hole and adjusts tension by turning it counter-clockwise. I have found
            Message 5 of 7 , Apr 1, 2002
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              My machine has a quick release screw that bears on a
              barrel nut that slips into the oval hole and adjusts
              tension by turning it counter-clockwise. I have found
              that adjusting the tension in this way will almost
              elininate the vibration caused by a non-concentric
              pulley/shaft combo I don't think that this is a stock
              option, but it works well and should be easy to
              duplicate for someone with a lathe (oops! I forgot who
              I was talking to!).



              G
              --- Jon Elson <elson@...> wrote:
              > chris111148198 wrote:
              >
              > > Hi Every one.I was wondering if any body knew
              > how the belt tenision
              > > between the motor and the counter shaft was sus
              > posed to be
              > > adjusted. . I noticed that there was a boss on the
              > motor base with a
              > > elongated hole in it. and a corrosponding hole in
              > line on the counter
              > > shaft bracket ( this hole is clearenced for a 3-8
              > bolt).I just do not
              > > understand how a bolt is susposed to be employed.
              > (unless i'am
              > > missing parts ,
              >
              > There is supposed to be a spring on that bolt.
              >
              > > The parts book shows a slightly different base in
              > > that it does not have the boss with its elongated
              > hole) I forgot to
              > > mention that this is a Atlas 10-th42 Horizontal
              > counter shaft,
              > > I have read all the postings on chatter and
              > vibration and i have
              > > segmented belts, I"am gettig 20 thou runout on the
              > large counter
              > > shaft pulley, dont't know if this is my problem or
              > not . It looks
              > > like the 3-4 bore is slightly wallowed out.
              >
              > Yup, this is not uncommon. What happens is the
              > setscrew gets loose, and
              > then the Zamak pulley works against the steel shaft,
              > and the steel wins
              > every time. the fix is to bore out the pulley and
              > then fit a steel hub
              > insert
              > into it. But, it is not so easy to do when the
              > lathe is down.
              >
              > Jon
              >
              >
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            • Ronald Thibault
              ... The missing bolt is at least part of your problem. It s purpose is to keep the motor from bouncing around while under load. With just the weight of the
              Message 6 of 7 , Apr 1, 2002
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                At 04:25 PM 3/31/02 +0000, you wrote:
                > Hi Every one.I was wondering if any body knew how the belt tenision
                >between the motor and the counter shaft was sus posed to be
                >adjusted. . I noticed that there was a boss on the motor base with a
                >elongated hole in it. and a corrosponding hole in line on the counter
                >shaft bracket ( this hole is clearenced for a 3-8 bolt).I just do not
                >understand how a bolt is susposed to be employed. (unless i'am
                >missing parts , The parts book shows a slightly different base in
                >that it does not have the boss with its elongated hole) I forgot to
                >mention that this is a Atlas 10-th42 Horizontal counter shaft,
                > I have read all the postings on chatter and vibration and i have
                >segmented belts, I"am gettig 20 thou runout on the large counter
                >shaft pulley, dont't know if this is my problem or not . It looks
                >like the 3-4 bore is slightly wallowed out. I'am thinking that this
                >is important as i see the balance (spot drilled on the pully)
                > Any help is appreciated Chris Miller

                The missing bolt is at least part of your problem. It's purpose
                is to keep the motor from bouncing around while under load. With just the
                weight of the motor holding it down the pulley climbs up the belt a little,
                until the loss of tension decreases the friction, and the motor falls back
                down. This repeats, and causes vibration. The bolt has nuts between the
                two holes that are used to push the mount away from the counter shaft
                base. Adjust the nuts so that the belt is a little loose with the belts
                not engaged, but tight when engaged.

                Ron Thibault
                Warrenville, SC USA
                Builder Miinie #2
                Captain R/C Combat Ship USS Arizona
                http://pages.prodigy.net/thibaultr/
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