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Re: Engineer help needed!

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  • cvlac
    Hi Do you know about the cost of the ball bar test system ? Costas ... lines, but when circular interpolation comes into play .003-.010 (or more) backlash like
    Message 1 of 21 , May 11, 2008
    • 0 Attachment
      Hi
      Do you know about the cost of the ball bar test system ?
      Costas

      --- In multimachine@yahoogroups.com, shawn c <shawncd1@...> wrote:
      >
      >
      > Your correct about backlash compensation when cutting straight
      lines, but when circular interpolation comes into play .003-.010 (or
      more) backlash like what is usually found in new and used acme screws
      wont be acceptable no matter how much comp you put into the equation.
      Trouble is when you try to cut a circle or radius with backlash each
      axis must back up and then back in forward to take out the backlash,
      this creates a very jagged motion. Now if you only have a few tenths
      of backlash that can be taken up with comp. Your required tolerances
      will have allot to do with what is tolerable. If you must use acme
      screws build an anti backlash nut. Two nuts (typically brass) side by
      side in a holder tightened slightly against each other and held in
      place. This is what was used years ago and in some instances today
      (sherline). The downfall is readjustment and more torque needed to
      turn the screws. A new technique is to use a product called mongolice
      which can be poured around the screw in a mold, after it sets up you
      have plastic nut that forms very tightly with minimal friction due to
      lowered sticktion additives.
      > Those of you that want to argue about this dont bother. Buy a ball
      bar test system and set your backlash adjustment with standard lead
      screws, setup a quick test and you can view for yourself the erratic
      undesirable movement.
      > A simple circular cut in aluminum will show the same results...
      >
      > Shop around for used or new ball screws. Allot of surplus is
      available on ebay. Rolled or ground, either will be better than acme
      lead screws......
      >
      > http://www.youtube.com/watch?v=4xt6ngxyq7w
      >
      >
      >
      >
      >
      > To: multimachine@...: pcoueffin@...: Sat, 10 May 2008 19:58:24 -
      0700Subject: Re: [multimachine] Re: Engineer help needed!
      >
      >
      >
      >
      > NC and CNC systems have been around a very long time. They've
      beendone on simple non-ballscrew machines. You jut need to program
      thesystem to compensate for backlash, which is not difficult.You
      seldom see modern industrial CNC on non-ballscrew machines,because
      the machines with ballscrews can run faster, and potentiallyhold
      tighter tolerances. You do see lots of hobby CNC conversionsusing
      plain leadscrews, and stepper motors bodged on where the handlesused
      to be. Given the emphasis that the multimachine group has
      putinto "good enough" design, I'll be very surprised if someone does
      notdo it eventually. Even 2-axis CNC with a manual Z axis would give
      youa lot of interesting options.>> Hi Pat>> Personaly I think that
      for CNC it is absolutely necessary to have>> real ballscrews (not
      ACME threads) and linear slides to all your>> mouvments.>>
      Costas>>>> --- In multimachine@yahoogroups.com, "Pat Delany"
      <rigmatch@>>> wrote:>> >>> > As usual I did not explain things
      well.>> > As the jack pressure is released, the vert. slide leans
      backward to>> > take up any play in the box ways. This really offends
      me even>> though I>> > am told that this is a common problem in knee
      mills that have a few>> > years of use on them.>> > Since I planned
      to try springs to reduce slide "stickiness", I>> thought>> > I would
      try a second set of springs to keep the table from "sagging">> >
      (slightly tilting down) as it is lowered.>> > In the remote chance
      all this would work, think of what we would>> have.>> > An easily
      built smooth acting slide that would stay parallel with>> the>> >
      spindle at all times! This would allow milling cuts without having>>
      to>> > tighten clamp bolts! Maybe CNC would be possible.>> >>> > I'm
      probably wrong.>> >>> > Pat>> > --- In
      multimachine@yahoogroups.com, "cvlac" <cvlac0@> wrote:>> > >>> > > Hi
      Keith>> > > Me too I have the same feeling, since I have not these
      problems>> > > because of the gibs that I have build in my vertical
      slide.To one>> side>> > > I have put a long square bronze gib that
      can be adjusted with>> some set>> > > screws, and all other screws
      are pushing some small bronze discs>> to>> > > protect the plates
      from their kiss.Ofcourse the square 10X19X400>> > > bronze gib was
      previously grind by hand .>> > > For the moment I'm trying to resolve
      an other MM problem.It>> seems>> > > that the compound slide is not
      very well suited for this job>> since it>> > > is not very
      precise .So I'm searching in ebay to find some low>> cost>> > >
      ballscrew and linear slides to adapt them to my equipment.>> > > An
      other problem is that the lathe chuck is not very useful>> for>> > >
      milling since the milling arbor runs out off center each time I'm>> >
      > milling something hard or the cutting depth is more than 1mm.>> > >
      So for milling, I'm trying to find some other solution like a low>>
      cost>> > > colette chuck using the taper bush products.>> > >
      Costas>> > >>> > > --- In multimachine@yahoogroups.com, keith
      gutshall <drpshops@>>> wrote:>> > > >>> > > > Hello Donald>> > > > I
      am feeling like you on the spring idea.>> > > > I dont think that
      spring is the answer to the problem.>> > > > I think that a good set
      of adjustable gibs and some>> runners/>> > > spacers down each side
      of the large flat plate.these could be>> 1/8 x>> > > 3/4-1 in crs
      just screwed to the plate.>> > > > The runners/ spacers are to keep
      the plates from touching in>> the>> > > middle. On a wide plate the
      middle if there is a bow in ,it will>> > > stick/ hangup.>> > > >
      There should be a gib on the side to keep any twist out of>> the>> >
      > slide.>> > > > There is a drawing in my photo folder drpshops1
      showing this.>> > > >>> > > > In my test I could move the vertical
      slide up/down in less>> than>> > > 0.0005in.I thought the small>> > >
      > test slide worked very good made like the drawing.>> > > > The hot
      rolled steel took a lot of cleaning up to work this>> good.>> > > >
      Keith>> > > > Donald H Locker <dhlocker@> wrote:>> > > > Hi, Pat.>> >
      > >>> > > > In my interpretation, the "main block" is the part which
      is>> > > stationary and the>> > > > "300 lb vert slide block and
      crossfeed" is the movable part. The>> > > springs you>> > > >
      indicate that "hold blocks together" must supply sufficient>> force>>
      > > that they>> > > > prevent the movable part from separating from
      the stationary>> part>> > > under the most>> > > > extreme separating
      forces.>> > > >>> > > > As drawn, the separating forces are due to
      gravity on the>> movable>> > > part, and the>> > > > minimum spring
      force would be ... see the ciphering below;>> someone>> > > else
      please>> > > > check me.>> > > >>> > > > 300 lbs, approximately 9
      inches from the pivot is 225 lbf-ft;>> the>> > > spring must>> > > >
      provide a force that exceeds the 225 divided by the distance>> from>>
      > > the bottom of>> > > > the stationary block to the spring
      attachment (in ft). The force>> > > applied by a>> > > > spring is
      equal to its "rate" (should be specified in the>> > > documentation
      for it,>> > > > or can be measured) multiplied by its deflection,
      plus any>> initial>> > set.>> > > >>> > > > A spring with a rate of
      500 lb/in, with an intial set of 50 lbs>> > > would require an>> > >
      > installed length of 3/8 inch if the attachment were one foot>>
      above>> > > the bottom of>> > > > the stationary block. More or less.
      (225 lbs needed - 50 lbs>> initial>> > > set) =>> > > > 175 lbs
      needed by stretching spring; (175 lbs)/(500 lbs/inch) =>> 0.35>> > >
      inches.>> > > > Round up to the nearest fraction.)>> > > >>> > > > In
      my opinion, rather than a spring, a set of gibs or guide-bars>> > >
      would be>> > > > better. These are essentially springs with _very_
      high spring>> rates>> > > and would>> > > > be more reliable.>> > >
      >>> > > > HTH,>> > > > Donald.>> > > >>> > > > Pat Delany wrote:>> >
      > > > In the photo folder "Vert slide springs", I put a crude>>
      drawing>> > of an>> > > > > MM with some vert slide springs added. I
      am going to try 2>> mower>> > deck>> > > > > springs to pull the
      block down but I do now know what kind of>> spring>> > > > > to use
      to hold the blocks together when jack pressure is>> released. I>> > >
      > > guess this is a simple engineering problem but I do not have>> a
      clue>> > > > > about solving it.>> > > > >>> > > > > Pat>> > > > >>>
      > > >>> > > >>> > > >>> > > >>> > > >>> > > > Deep Run Portage>> > >
      > Back Shop>> > > > " The Lizard Works">> > > >>> > > > --------------
      ------------------->> > > > Be a better friend, newshound, and know-
      it-all with Yahoo!>> Mobile.>> > > Try it now.>> > > >>> > >>> >>>>>
      >
    • shawn c
      Theres a used system on ebay for $1000, but it hasnt met reserve. I purchased mine several years ago for about $5000. To: multimachine@yahoogroups.comFrom:
      Message 2 of 21 , May 11, 2008
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        Theres a used system on ebay for $1000, but it hasnt met reserve. I purchased mine several years ago for about $5000.


         

        To: multimachine@yahoogroups.com
        From: cvlac0@...
        Date: Sun, 11 May 2008 17:40:34 +0000
        Subject: [multimachine] Re: Engineer help needed!

        Hi
        Do you know about the cost of the ball bar test system ?
        Costas

        --- In multimachine@ yahoogroups. com, shawn c <shawncd1@.. .> wrote:
        >
        >
        > Your correct about backlash compensation when cutting straight
        lines, but when circular interpolation comes into play .003-.010 (or
        more) backlash like what is usually found in new and used acme screws
        wont be acceptable no matter how much comp you put into the equation.
        Trouble is when you try to cut a circle or radius with backlash each
        axis must back up and then back in forward to take out the backlash,
        this creates a very jagged motion. Now if you only have a few tenths
        of backlash that can be taken up with comp. Your required tolerances
        will have allot to do with what is tolerable. If you must use acme
        screws build an anti backlash nut. Two nuts (typically brass) side by
        side in a holder tightened slightly against each other and held in
        place. This is what was used years ago and in some instances today
        (sherline). The downfall is readjustment and more torque needed to
        turn the screws. A new technique is to use a product called mongolice
        which can be poured around the screw in a mold, after it sets up you
        have plastic nut that forms very tightly with minimal friction due to
        lowered sticktion additives.
        > Those of you that want to argue about this dont bother. Buy a ball
        bar test system and set your backlash adjustment with standard lead
        screws, setup a quick test and you can view for yourself the erratic
        undesirable movement.
        > A simple circular cut in aluminum will show the same results...
        >
        > Shop around for used or new ball screws. Allot of surplus is
        available on ebay. Rolled or ground, either will be better than acme
        lead screws......
        >
        > http://www.youtube. com/watch? v=4xt6ngxyq7w
        >
        >
        >
        >
        >
        > To: multimachine@ ...: pcoueffin@.. .: Sat, 10 May 2008 19:58:24 -
        0700Subject: Re: [multimachine] Re: Engineer help needed!
        >
        >
        >
        >
        > NC and CNC systems have been around a very long time. They've
        beendone on simple non-ballscrew machines. You jut need to program
        thesystem to compensate for backlash, which is not difficult.You
        seldom see modern industrial CNC on non-ballscrew machines,because
        the machines with ballscrews can run faster, and potentiallyhold
        tighter tolerances. You do see lots of hobby CNC conversionsusing
        plain leadscrews, and stepper motors bodged on where the handlesused
        to be. Given the emphasis that the multimachine group has
        putinto "good enough" design, I'll be very surprised if someone does
        notdo it eventually. Even 2-axis CNC with a manual Z axis would give
        youa lot of interesting options.>> Hi Pat>> Personaly I think that
        for CNC it is absolutely necessary to have>> real ballscrews (not
        ACME threads) and linear slides to all your>> mouvments.>>
        Costas>>>> --- In multimachine@ yahoogroups. com, "Pat Delany"
        <rigmatch@>> > wrote:>> >>> > As usual I did not explain things
        well.>> > As the jack pressure is released, the vert. slide leans
        backward to>> > take up any play in the box ways. This really offends
        me even>> though I>> > am told that this is a common problem in knee
        mills that have a few>> > years of use on them.>> > Since I planned
        to try springs to reduce slide "stickiness" , I>> thought>> > I would
        try a second set of springs to keep the table from "sagging">> >
        (slightly tilting down) as it is lowered.>> > In the remote chance
        all this would work, think of what we would>> have.>> > An easily
        built smooth acting slide that would stay parallel with>> the>> >
        spindle at all times! This would allow milling cuts without having>>
        to>> > tighten clamp bolts! Maybe CNC would be possible.>> >>> > I'm
        probably wrong.>> >>> > Pat>> > --- In
        multimachine@ yahoogroups. com, "cvlac" <cvlac0@> wrote:>> > >>> > > Hi
        Keith>> > > Me too I have the same feeling, since I have not these
        problems>> > > because of the gibs that I have build in my vertical
        slide.To one>> side>> > > I have put a long square bronze gib that
        can be adjusted with>> some set>> > > screws, and all other screws
        are pushing some small bronze discs>> to>> > > protect the plates
        from their kiss.Ofcourse the square 10X19X400>> > > bronze gib was
        previously grind by hand .>> > > For the moment I'm trying to resolve
        an other MM problem.It>> seems>> > > that the compound slide is not
        very well suited for this job>> since it>> > > is not very
        precise .So I'm searching in ebay to find some low>> cost>> > >
        ballscrew and linear slides to adapt them to my equipment.>> > > An
        other problem is that the lathe chuck is not very useful>> for>> > >
        milling since the milling arbor runs out off center each time I'm>> >
        > milling something hard or the cutting depth is more than 1mm.>> > >
        So for milling, I'm trying to find some other solution like a low>>
        cost>> > > colette chuck using the taper bush products.>> > >
        Costas>> > >>> > > --- In multimachine@ yahoogroups. com, keith
        gutshall <drpshops@>> > wrote:>> > > >>> > > > Hello Donald>> > > > I
        am feeling like you on the spring idea.>> > > > I dont think that
        spring is the answer to the problem.>> > > > I think that a good set
        of adjustable gibs and some>> runners/>> > > spacers down each side
        of the large flat plate.these could be>> 1/8 x>> > > 3/4-1 in crs
        just screwed to the plate.>> > > > The runners/ spacers are to keep
        the plates from touching in>> the>> > > middle. On a wide plate the
        middle if there is a bow in ,it will>> > > stick/ hangup.>> > > >
        There should be a gib on the side to keep any twist out of>> the>> >
        > slide.>> > > > There is a drawing in my photo folder drpshops1
        showing this.>> > > >>> > > > In my test I could move the vertical
        slide up/down in less>> than>> > > 0.0005in.I thought the small>> > >
        > test slide worked very good made like the drawing.>> > > > The hot
        rolled steel took a lot of cleaning up to work this>> good.>> > > >
        Keith>> > > > Donald H Locker <dhlocker@> wrote:>> > > > Hi, Pat.>> >
        > >>> > > > In my interpretation, the "main block" is the part which
        is>> > > stationary and the>> > > > "300 lb vert slide block and
        crossfeed" is the movable part. The>> > > springs you>> > > >
        indicate that "hold blocks together" must supply sufficient>> force>>
        > > that they>> > > > prevent the movable part from separating from
        the stationary>> part>> > > under the most>> > > > extreme separating
        forces.>> > > >>> > > > As drawn, the separating forces are due to
        gravity on the>> movable>> > > part, and the>> > > > minimum spring
        force would be ... see the ciphering below;>> someone>> > > else
        please>> > > > check me.>> > > >>> > > > 300 lbs, approximately 9
        inches from the pivot is 225 lbf-ft;>> the>> > > spring must>> > > >
        provide a force that exceeds the 225 divided by the distance>> from>>
        > > the bottom of>> > > > the stationary block to the spring
        attachment (in ft). The force>> > > applied by a>> > > > spring is
        equal to its "rate" (should be specified in the>> > > documentation
        for it,>> > > > or can be measured) multiplied by its deflection,
        plus any>> initial>> > set.>> > > >>> > > > A spring with a rate of
        500 lb/in, with an intial set of 50 lbs>> > > would require an>> > >
        > installed length of 3/8 inch if the attachment were one foot>>
        above>> > > the bottom of>> > > > the stationary block. More or less.
        (225 lbs needed - 50 lbs>> initial>> > > set) =>> > > > 175 lbs
        needed by stretching spring; (175 lbs)/(500 lbs/inch) =>> 0.35>> > >
        inches.>> > > > Round up to the nearest fraction.)>> > > >>> > > > In
        my opinion, rather than a spring, a set of gibs or guide-bars>> > >
        would be>> > > > better. These are essentially springs with _very_
        high spring>> rates>> > > and would>> > > > be more reliable.>> > >
        >>> > > > HTH,>> > > > Donald.>> > > >>> > > > Pat Delany wrote:>> >
        > > > In the photo folder "Vert slide springs", I put a crude>>
        drawing>> > of an>> > > > > MM with some vert slide springs added. I
        am going to try 2>> mower>> > deck>> > > > > springs to pull the
        block down but I do now know what kind of>> spring>> > > > > to use
        to hold the blocks together when jack pressure is>> released. I>> > >
        > > guess this is a simple engineering problem but I do not have>> a
        clue>> > > > > about solving it.>> > > > >>> > > > > Pat>> > > > >>>
        > > >>> > > >>> > > >>> > > >>> > > >>> > > > Deep Run Portage>> > >
        > Back Shop>> > > > " The Lizard Works">> > > >>> > > > ------------ --
        ------------ ------->> > > > Be a better friend, newshound, and know-
        it-all with Yahoo!>> Mobile.>> > > Try it now.>> > > >>> > >>> >>>>>
        >


      • Pat Delany
        Thanks Pierre If it gets as close as an Electronic Lead Screw, I would be very happy. I ll admit though that I have trouble visualizing even an ELS when the
        Message 3 of 21 , May 11, 2008
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          Thanks Pierre

          If it gets as close as an Electronic Lead Screw, I
          would be very happy. I'll admit though that I have
          trouble visualizing even an ELS when the end mill
          comes from the side instead of the top. Maybe some of
          you younger and more experienced guys can help with
          this (the z axis really being the y axis!).

          Pat

          --- Pierre Coueffin <pcoueffin@...> wrote:

          > NC and CNC systems have been around a very long
          > time. They've been
          > done on simple non-ballscrew machines. You jut need
          > to program the
          > system to compensate for backlash, which is not
          > difficult.
          >
          > You seldom see modern industrial CNC on
          > non-ballscrew machines,
          > because the machines with ballscrews can run faster,
          > and potentially
          > hold tighter tolerances. You do see lots of hobby
          > CNC conversions
          > using plain leadscrews, and stepper motors bodged on
          > where the handles
          > used to be. Given the emphasis that the
          > multimachine group has put
          > into "good enough" design, I'll be very surprised if
          > someone does not
          > do it eventually. Even 2-axis CNC with a manual Z
          > axis would give you
          > a lot of interesting options.
          >
          > >> Hi Pat
          > >> Personaly I think that for CNC it is absolutely
          > necessary to have
          > >> real ballscrews (not ACME threads) and linear
          > slides to all your
          > >> mouvments.
          > >> Costas
          > >>
          > >> --- In multimachine@yahoogroups.com, "Pat Delany"
          > <rigmatch@>
          > >> wrote:
          > >> >
          > >> > As usual I did not explain things well.
          > >> > As the jack pressure is released, the vert.
          > slide leans backward to
          > >> > take up any play in the box ways. This really
          > offends me even
          > >> though I
          > >> > am told that this is a common problem in knee
          > mills that have a few
          > >> > years of use on them.
          > >> > Since I planned to try springs to reduce slide
          > "stickiness", I
          > >> thought
          > >> > I would try a second set of springs to keep the
          > table from "sagging"
          > >> > (slightly tilting down) as it is lowered.
          > >> > In the remote chance all this would work, think
          > of what we would
          > >> have.
          > >> > An easily built smooth acting slide that would
          > stay parallel with
          > >> the
          > >> > spindle at all times! This would allow milling
          > cuts without having
          > >> to
          > >> > tighten clamp bolts! Maybe CNC would be
          > possible.
          > >> >
          > >> > I'm probably wrong.
          > >> >
          > >> > Pat
          > >> > --- In multimachine@yahoogroups.com, "cvlac"
          > <cvlac0@> wrote:
          > >> > >
          > >> > > Hi Keith
          > >> > > Me too I have the same feeling, since I have
          > not these problems
          > >> > > because of the gibs that I have build in my
          > vertical slide.To one
          > >> side
          > >> > > I have put a long square bronze gib that can
          > be adjusted with
          > >> some set
          > >> > > screws, and all other screws are pushing some
          > small bronze discs
          > >> to
          > >> > > protect the plates from their kiss.Ofcourse
          > the square 10X19X400
          > >> > > bronze gib was previously grind by hand .
          > >> > > For the moment I'm trying to resolve an other
          > MM problem.It
          > >> seems
          > >> > > that the compound slide is not very well
          > suited for this job
          > >> since it
          > >> > > is not very precise .So I'm searching in ebay
          > to find some low
          > >> cost
          > >> > > ballscrew and linear slides to adapt them to
          > my equipment.
          > >> > > An other problem is that the lathe chuck is
          > not very useful
          > >> for
          > >> > > milling since the milling arbor runs out off
          > center each time I'm
          > >> > > milling something hard or the cutting depth
          > is more than 1mm.
          > >> > > So for milling, I'm trying to find some other
          > solution like a low
          > >> cost
          > >> > > colette chuck using the taper bush products.
          > >> > > Costas
          > >> > >
          > >> > > --- In multimachine@yahoogroups.com, keith
          > gutshall <drpshops@>
          > >> wrote:
          > >> > > >
          > >> > > > Hello Donald
          > >> > > > I am feeling like you on the spring idea.
          > >> > > > I dont think that spring is the answer to
          > the problem.
          > >> > > > I think that a good set of adjustable gibs
          > and some
          > >> runners/
          > >> > > spacers down each side of the large flat
          > plate.these could be
          > >> 1/8 x
          > >> > > 3/4-1 in crs just screwed to the plate.
          > >> > > > The runners/ spacers are to keep the plates
          > from touching in
          > >> the
          > >> > > middle. On a wide plate the middle if there
          > is a bow in ,it will
          > >> > > stick/ hangup.
          > >> > > > There should be a gib on the side to keep
          > any twist out of
          > >> the
          > >> > > slide.
          > >> > > > There is a drawing in my photo folder
          > drpshops1 showing this.
          > >> > > >
          > >> > > > In my test I could move the vertical slide
          > up/down in less
          > >> than
          > >> > > 0.0005in.I thought the small
          > >> > > > test slide worked very good made like the
          > drawing.
          > >> > > > The hot rolled steel took a lot of cleaning
          > up to work this
          > >> good.
          > >> > > > Keith
          > >> > > > Donald H Locker <dhlocker@> wrote:
          > >> > > > Hi, Pat.
          > >> > > >
          > >> > > > In my interpretation, the "main block" is
          > the part which is
          > >> > > stationary and the
          > >> > > > "300 lb vert slide block and crossfeed" is
          > the movable part. The
          > >> > > springs you
          > >> > > > indicate that "hold blocks together" must
          > supply sufficient
          > >> force
          > >> > > that they
          > >> > > > prevent the movable part from separating
          > from the stationary
          > >> part
          > >> > > under the most
          > >> > > > extreme separating forces.
          > >> > > >
          > >> > > > As drawn, the separating forces are due to
          > gravity on the
          > >> movable
          > >> > > part, and the
          > >> > > > minimum spring force would be ... see the
          > ciphering below;
          > >> someone
          > >> > > else please
          > >> > > > check me.
          > >> > > >
          > >> > > > 300 lbs, approximately 9 inches from the
          > pivot is 225 lbf-ft;
          > >> the
          > >> > > spring must
          > >> > > > provide a force that exceeds the 225
          > divided by the distance
          > >> from
          > >> > > the bottom of
          > >> > > > the stationary block to the spring
          > attachment (in ft). The force
          > >> > > applied by a
          > >> > > > spring is equal to its "rate" (should be
          > specified in the
          > >> > > documentation for it,
          > >> > > > or can be measured) multiplied by its
          > deflection, plus any
          > >> initial
          > >> > set.
          > >> > > >
          > >> > > > A spring with a rate of 500 lb/in, with an
          > intial set of 50 lbs
          > >> > > would require an
          > >> > > > installed length of 3/8 inch if the
          > attachment were one foot
          > >> above
          > >> > > the bottom of
          > >> > > > the stationary block. More or less. (225
          > lbs
          === message truncated ===



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        • a1g2r3i
          Dear Pat Though I tend to favour the posts that propose ways, gibs and gib screws; if you have your mind set on springs to keep the parts close together, have
          Message 4 of 21 , May 11, 2008
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            Dear Pat
            Though I tend to favour the posts that propose ways, gibs and gib
            screws; if you have your mind set on springs to keep the parts close
            together, have you thought of using valute type springs? Valute
            springs are what are used on heavy vehicles like buldozers and such,
            only use miniture valute. Perhaps wind some from 1 inch flat iron and
            get it tempered. I am also wondering if I remember valve springs that
            have a valute spring inside a coil spring.
            dennis mac

            --- In multimachine@yahoogroups.com, "Pat Delany" <rigmatch@...> wrote:
            >
            > As usual I did not explain things well.
            > As the jack pressure is released, the vert. slide leans backward to
            > take up any play in the box ways. This really offends me even though I
            > am told that this is a common problem in knee mills that have a few
            > years of use on them.
            > Since I planned to try springs to reduce slide "stickiness", I thought
            > I would try a second set of springs to keep the table from "sagging"
            > (slightly tilting down) as it is lowered.
            > In the remote chance all this would work, think of what we would have.
            > An easily built smooth acting slide that would stay parallel with the
            > spindle at all times! This would allow milling cuts without having to
            > tighten clamp bolts! Maybe CNC would be possible.
            >
            > I'm probably wrong.
            >
            > Pat
            > --- In multimachine@yahoogroups.com, "cvlac" <cvlac0@> wrote:
            > >
            > > Hi Keith
            > > Me too I have the same feeling, since I have not these problems
            > > because of the gibs that I have build in my vertical slide.To one side
            > > I have put a long square bronze gib that can be adjusted with some set
            > > screws, and all other screws are pushing some small bronze discs to
            > > protect the plates from their kiss.Ofcourse the square 10X19X400
            > > bronze gib was previously grind by hand .
            > > For the moment I'm trying to resolve an other MM problem.It seems
            > > that the compound slide is not very well suited for this job since it
            > > is not very precise .So I'm searching in ebay to find some low cost
            > > ballscrew and linear slides to adapt them to my equipment.
            > > An other problem is that the lathe chuck is not very useful for
            > > milling since the milling arbor runs out off center each time I'm
            > > milling something hard or the cutting depth is more than 1mm.
            > > So for milling, I'm trying to find some other solution like a low cost
            > > colette chuck using the taper bush products.
            > > Costas
            > >
            > > --- In multimachine@yahoogroups.com, keith gutshall <drpshops@> wrote:
            > > >
            > > > Hello Donald
            > > > I am feeling like you on the spring idea.
            > > > I dont think that spring is the answer to the problem.
            > > > I think that a good set of adjustable gibs and some runners/
            > > spacers down each side of the large flat plate.these could be 1/8 x
            > > 3/4-1 in crs just screwed to the plate.
            > > > The runners/ spacers are to keep the plates from touching in the
            > > middle. On a wide plate the middle if there is a bow in ,it will
            > > stick/ hangup.
            > > > There should be a gib on the side to keep any twist out of the
            > > slide.
            > > > There is a drawing in my photo folder drpshops1 showing this.
            > > >
            > > > In my test I could move the vertical slide up/down in less than
            > > 0.0005in.I thought the small
            > > > test slide worked very good made like the drawing.
            > > > The hot rolled steel took a lot of cleaning up to work this good.
            > > > Keith
            > > > Donald H Locker <dhlocker@> wrote:
            > > > Hi, Pat.
            > > >
            > > > In my interpretation, the "main block" is the part which is
            > > stationary and the
            > > > "300 lb vert slide block and crossfeed" is the movable part. The
            > > springs you
            > > > indicate that "hold blocks together" must supply sufficient force
            > > that they
            > > > prevent the movable part from separating from the stationary part
            > > under the most
            > > > extreme separating forces.
            > > >
            > > > As drawn, the separating forces are due to gravity on the movable
            > > part, and the
            > > > minimum spring force would be ... see the ciphering below; someone
            > > else please
            > > > check me.
            > > >
            > > > 300 lbs, approximately 9 inches from the pivot is 225 lbf-ft; the
            > > spring must
            > > > provide a force that exceeds the 225 divided by the distance from
            > > the bottom of
            > > > the stationary block to the spring attachment (in ft). The force
            > > applied by a
            > > > spring is equal to its "rate" (should be specified in the
            > > documentation for it,
            > > > or can be measured) multiplied by its deflection, plus any initial
            > set.
            > > >
            > > > A spring with a rate of 500 lb/in, with an intial set of 50 lbs
            > > would require an
            > > > installed length of 3/8 inch if the attachment were one foot above
            > > the bottom of
            > > > the stationary block. More or less. (225 lbs needed - 50 lbs initial
            > > set) =
            > > > 175 lbs needed by stretching spring; (175 lbs)/(500 lbs/inch) = 0.35
            > > inches.
            > > > Round up to the nearest fraction.)
            > > >
            > > > In my opinion, rather than a spring, a set of gibs or guide-bars
            > > would be
            > > > better. These are essentially springs with _very_ high spring rates
            > > and would
            > > > be more reliable.
            > > >
            > > > HTH,
            > > > Donald.
            > > >
            > > > Pat Delany wrote:
            > > > > In the photo folder "Vert slide springs", I put a crude drawing
            > of an
            > > > > MM with some vert slide springs added. I am going to try 2 mower
            > deck
            > > > > springs to pull the block down but I do now know what kind of
            spring
            > > > > to use to hold the blocks together when jack pressure is
            released. I
            > > > > guess this is a simple engineering problem but I do not have a
            clue
            > > > > about solving it.
            > > > >
            > > > > Pat
            > > > >
            > > >
            > > >
            > > >
            > > >
            > > >
            > > > Deep Run Portage
            > > > Back Shop
            > > > " The Lizard Works"
            > > >
            > > > ---------------------------------
            > > > Be a better friend, newshound, and know-it-all with Yahoo! Mobile.
            > > Try it now.
            > > >
            > >
            >
          • Darwin Wandler
            350 Chev cylinder heads exhaust valve and it has 160 to 280 lbs force depending on performance type. Any rebuilder would donate some to your cause as they
            Message 5 of 21 , May 12, 2008
            • 0 Attachment
              350 Chev cylinder heads exhaust valve and it has 160 to 280 lbs
              force depending on performance type. Any rebuilder would donate
              some to your cause as they throw out so many that don't match in a
              set when assembling.
              Darwin

              a1g2r3i wrote:
              >
              > Dear Pat
              > Though I tend to favour the posts that propose ways, gibs and gib
              > screws; if you have your mind set on springs to keep the parts close
              > together, have you thought of using valute type springs? Valute
              > springs are what are used on heavy vehicles like buldozers and such,
              > only use miniture valute. Perhaps wind some from 1 inch flat iron and
              > get it tempered. I am also wondering if I remember valve springs that
              > have a valute spring inside a coil spring.
              > dennis mac
              >
              > --- In multimachine@yahoogroups.com
              > <mailto:multimachine%40yahoogroups.com>, "Pat Delany" <rigmatch@...>
              > wrote:
              > >
              > > As usual I did not explain things well.
              > > As the jack pressure is released, the vert. slide leans backward to
              > > take up any play in the box ways. This really offends me even though I
              > > am told that this is a common problem in knee mills that have a few
              > > years of use on them.
              > > Since I planned to try springs to reduce slide "stickiness", I thought
              > > I would try a second set of springs to keep the table from "sagging"
              > > (slightly tilting down) as it is lowered.
              > > In the remote chance all this would work, think of what we would have.
              > > An easily built smooth acting slide that would stay parallel with the
              > > spindle at all times! This would allow milling cuts without having to
              > > tighten clamp bolts! Maybe CNC would be possible.
              > >
              > > I'm probably wrong.
              > >
              > > Pat
              > > --- In multimachine@yahoogroups.com
              > <mailto:multimachine%40yahoogroups.com>, "cvlac" <cvlac0@> wrote:
              > > >
              > > > Hi Keith
              > > > Me too I have the same feeling, since I have not these problems
              > > > because of the gibs that I have build in my vertical slide.To one side
              > > > I have put a long square bronze gib that can be adjusted with some set
              > > > screws, and all other screws are pushing some small bronze discs to
              > > > protect the plates from their kiss.Ofcourse the square 10X19X400
              > > > bronze gib was previously grind by hand .
              > > > For the moment I'm trying to resolve an other MM problem.It seems
              > > > that the compound slide is not very well suited for this job since it
              > > > is not very precise .So I'm searching in ebay to find some low cost
              > > > ballscrew and linear slides to adapt them to my equipment.
              > > > An other problem is that the lathe chuck is not very useful for
              > > > milling since the milling arbor runs out off center each time I'm
              > > > milling something hard or the cutting depth is more than 1mm.
              > > > So for milling, I'm trying to find some other solution like a low cost
              > > > colette chuck using the taper bush products.
              > > > Costas
              > > >
              > > > --- In multimachine@yahoogroups.com
              > <mailto:multimachine%40yahoogroups.com>, keith gutshall <drpshops@> wrote:
              > > > >
              > > > > Hello Donald
              > > > > I am feeling like you on the spring idea.
              > > > > I dont think that spring is the answer to the problem.
              > > > > I think that a good set of adjustable gibs and some runners/
              > > > spacers down each side of the large flat plate.these could be 1/8 x
              > > > 3/4-1 in crs just screwed to the plate.
              > > > > The runners/ spacers are to keep the plates from touching in the
              > > > middle. On a wide plate the middle if there is a bow in ,it will
              > > > stick/ hangup.
              > > > > There should be a gib on the side to keep any twist out of the
              > > > slide.
              > > > > There is a drawing in my photo folder drpshops1 showing this.
              > > > >
              > > > > In my test I could move the vertical slide up/down in less than
              > > > 0.0005in.I thought the small
              > > > > test slide worked very good made like the drawing.
              > > > > The hot rolled steel took a lot of cleaning up to work this good.
              > > > > Keith
              > > > > Donald H Locker <dhlocker@> wrote:
              > > > > Hi, Pat.
              > > > >
              > > > > In my interpretation, the "main block" is the part which is
              > > > stationary and the
              > > > > "300 lb vert slide block and crossfeed" is the movable part. The
              > > > springs you
              > > > > indicate that "hold blocks together" must supply sufficient force
              > > > that they
              > > > > prevent the movable part from separating from the stationary part
              > > > under the most
              > > > > extreme separating forces.
              > > > >
              > > > > As drawn, the separating forces are due to gravity on the movable
              > > > part, and the
              > > > > minimum spring force would be ... see the ciphering below; someone
              > > > else please
              > > > > check me.
              > > > >
              > > > > 300 lbs, approximately 9 inches from the pivot is 225 lbf-ft; the
              > > > spring must
              > > > > provide a force that exceeds the 225 divided by the distance from
              > > > the bottom of
              > > > > the stationary block to the spring attachment (in ft). The force
              > > > applied by a
              > > > > spring is equal to its "rate" (should be specified in the
              > > > documentation for it,
              > > > > or can be measured) multiplied by its deflection, plus any initial
              > > set.
              > > > >
              > > > > A spring with a rate of 500 lb/in, with an intial set of 50 lbs
              > > > would require an
              > > > > installed length of 3/8 inch if the attachment were one foot above
              > > > the bottom of
              > > > > the stationary block. More or less. (225 lbs needed - 50 lbs initial
              > > > set) =
              > > > > 175 lbs needed by stretching spring; (175 lbs)/(500 lbs/inch) = 0.35
              > > > inches.
              > > > > Round up to the nearest fraction.)
              > > > >
              > > > > In my opinion, rather than a spring, a set of gibs or guide-bars
              > > > would be
              > > > > better. These are essentially springs with _very_ high spring rates
              > > > and would
              > > > > be more reliable.
              > > > >
              > > > > HTH,
              > > > > Donald.
              > > > >
              > > > > Pat Delany wrote:
              > > > > > In the photo folder "Vert slide springs", I put a crude drawing
              > > of an
              > > > > > MM with some vert slide springs added. I am going to try 2 mower
              > > deck
              > > > > > springs to pull the block down but I do now know what kind of
              > spring
              > > > > > to use to hold the blocks together when jack pressure is
              > released. I
              > > > > > guess this is a simple engineering problem but I do not have a
              > clue
              > > > > > about solving it.
              > > > > >
              > > > > > Pat
              > > > > >
              > > > >
              > > > >
              > > > >
              > > > >
              > > > >
              > > > > Deep Run Portage
              > > > > Back Shop
              > > > > " The Lizard Works"
              > > > >
              > > > > ---------------------------------
              > > > > Be a better friend, newshound, and know-it-all with Yahoo! Mobile.
              > > > Try it now.
              > > > >
              > > >
              > >
              >
              >
            • Pat Delany
              I have really screwed up explaining this idea! Let me try again. Dovetail or box ways both have the same problem when they support just one side of a heavy
              Message 6 of 21 , May 12, 2008
              • 0 Attachment
                I have really screwed up explaining this idea! Let me
                try again.
                Dovetail or box ways both have the same problem when
                they support just one side of a heavy weight. If they
                are loose enough to let the weight slide down then the
                vert.slide is going to "sag" a little when the clamps
                are loosened and the jack pressure is lowered. The
                heavy horizontal spring is meant to do just one thing,
                stop this "sag" (probably as little as 10 thou.) The
                vertical spring is to relieve any "stickiness" of the
                slide caused by added jack pressure.

                Pat


                --- a1g2r3i <a1g2r3i@...> wrote:

                > Dear Pat
                > Though I tend to favour the posts that propose
                > ways, gibs and gib
                > screws; if you have your mind set on springs to keep
                > the parts close
                > together, have you thought of using valute type
                > springs? Valute
                > springs are what are used on heavy vehicles like
                > buldozers and such,
                > only use miniture valute. Perhaps wind some from 1
                > inch flat iron and
                > get it tempered. I am also wondering if I remember
                > valve springs that
                > have a valute spring inside a coil spring.
                > dennis mac
                >
                > --- In multimachine@yahoogroups.com, "Pat Delany"
                > <rigmatch@...> wrote:
                > >
                > > As usual I did not explain things well.
                > > As the jack pressure is released, the vert. slide
                > leans backward to
                > > take up any play in the box ways. This really
                > offends me even though I
                > > am told that this is a common problem in knee
                > mills that have a few
                > > years of use on them.
                > > Since I planned to try springs to reduce slide
                > "stickiness", I thought
                > > I would try a second set of springs to keep the
                > table from "sagging"
                > > (slightly tilting down) as it is lowered.
                > > In the remote chance all this would work, think of
                > what we would have.
                > > An easily built smooth acting slide that would
                > stay parallel with the
                > > spindle at all times! This would allow milling
                > cuts without having to
                > > tighten clamp bolts! Maybe CNC would be possible.
                > >
                > > I'm probably wrong.
                > >
                > > Pat
                > > --- In multimachine@yahoogroups.com, "cvlac"
                > <cvlac0@> wrote:
                > > >
                > > > Hi Keith
                > > > Me too I have the same feeling, since I have not
                > these problems
                > > > because of the gibs that I have build in my
                > vertical slide.To one side
                > > > I have put a long square bronze gib that can be
                > adjusted with some set
                > > > screws, and all other screws are pushing some
                > small bronze discs to
                > > > protect the plates from their kiss.Ofcourse the
                > square 10X19X400
                > > > bronze gib was previously grind by hand .
                > > > For the moment I'm trying to resolve an other
                > MM problem.It seems
                > > > that the compound slide is not very well suited
                > for this job since it
                > > > is not very precise .So I'm searching in ebay to
                > find some low cost
                > > > ballscrew and linear slides to adapt them to my
                > equipment.
                > > > An other problem is that the lathe chuck is
                > not very useful for
                > > > milling since the milling arbor runs out off
                > center each time I'm
                > > > milling something hard or the cutting depth is
                > more than 1mm.
                > > > So for milling, I'm trying to find some other
                > solution like a low cost
                > > > colette chuck using the taper bush products.
                > > > Costas
                > > >
                > > > --- In multimachine@yahoogroups.com, keith
                > gutshall <drpshops@> wrote:
                > > > >
                > > > > Hello Donald
                > > > > I am feeling like you on the spring idea.
                > > > > I dont think that spring is the answer to
                > the problem.
                > > > > I think that a good set of adjustable gibs
                > and some runners/
                > > > spacers down each side of the large flat
                > plate.these could be 1/8 x
                > > > 3/4-1 in crs just screwed to the plate.
                > > > > The runners/ spacers are to keep the plates
                > from touching in the
                > > > middle. On a wide plate the middle if there is a
                > bow in ,it will
                > > > stick/ hangup.
                > > > > There should be a gib on the side to keep
                > any twist out of the
                > > > slide.
                > > > > There is a drawing in my photo folder
                > drpshops1 showing this.
                > > > >
                > > > > In my test I could move the vertical slide
                > up/down in less than
                > > > 0.0005in.I thought the small
                > > > > test slide worked very good made like the
                > drawing.
                > > > > The hot rolled steel took a lot of cleaning
                > up to work this good.
                > > > > Keith
                > > > > Donald H Locker <dhlocker@> wrote:
                > > > > Hi, Pat.
                > > > >
                > > > > In my interpretation, the "main block" is the
                > part which is
                > > > stationary and the
                > > > > "300 lb vert slide block and crossfeed" is the
                > movable part. The
                > > > springs you
                > > > > indicate that "hold blocks together" must
                > supply sufficient force
                > > > that they
                > > > > prevent the movable part from separating from
                > the stationary part
                > > > under the most
                > > > > extreme separating forces.
                > > > >
                > > > > As drawn, the separating forces are due to
                > gravity on the movable
                > > > part, and the
                > > > > minimum spring force would be ... see the
                > ciphering below; someone
                > > > else please
                > > > > check me.
                > > > >
                > > > > 300 lbs, approximately 9 inches from the pivot
                > is 225 lbf-ft; the
                > > > spring must
                > > > > provide a force that exceeds the 225 divided
                > by the distance from
                > > > the bottom of
                > > > > the stationary block to the spring attachment
                > (in ft). The force
                > > > applied by a
                > > > > spring is equal to its "rate" (should be
                > specified in the
                > > > documentation for it,
                > > > > or can be measured) multiplied by its
                > deflection, plus any initial
                > > set.
                > > > >
                > > > > A spring with a rate of 500 lb/in, with an
                > intial set of 50 lbs
                > > > would require an
                > > > > installed length of 3/8 inch if the attachment
                > were one foot above
                > > > the bottom of
                > > > > the stationary block. More or less. (225 lbs
                > needed - 50 lbs initial
                > > > set) =
                > > > > 175 lbs needed by stretching spring; (175
                > lbs)/(500 lbs/inch) = 0.35
                > > > inches.
                > > > > Round up to the nearest fraction.)
                > > > >
                > > > > In my opinion, rather than a spring, a set of
                > gibs or guide-bars
                > > > would be
                > > > > better. These are essentially springs with
                > _very_ high spring rates
                > > > and would
                > > > > be more reliable.
                > > > >
                > > > > HTH,
                > > > > Donald.
                > > > >
                > > > > Pat Delany wrote:
                > > > > > In the photo folder "Vert slide springs", I
                > put a crude drawing
                > > of an
                > > > > > MM with some vert slide springs added. I am
                > going to try 2 mower
                > > deck
                > > > > > springs to pull the block down but I do now
                > know what kind of
                > spring
                > > > > > to use to hold the blocks together when jack
                > pressure is
                > released. I
                > > > > > guess this is a simple engineering problem
                > but I do not have a
                > clue
                > > > > > about solving it.
                > > > > >
                > > > > > Pat
                > > > > >
                > > > >
                > > > >
                > > > >
                > > > >
                > > > >
                > > > > Deep Run Portage
                > > > > Back Shop
                >
                === message truncated ===



                ____________________________________________________________________________________
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                know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
              • jimyjak1
                Hi Pat and All If the jack is centered under the weight there will be no sag and no need for springs. You could even move the jack just a bit forward to make
                Message 7 of 21 , May 12, 2008
                • 0 Attachment
                  Hi Pat and All
                  If the jack is centered under the weight there will be no sag and no
                  need for springs. You could even move the jack just a bit forward to
                  make the weight lean into the big block. Never place the jack close to
                  the big block as this will cause sag and undue ware on the ways. Just
                  the thoughts of an old jack of all trades.
                  jimyjack

                  --- In multimachine@yahoogroups.com, Pat Delany <rigmatch@...> wrote:
                  >
                  > I have really screwed up explaining this idea! Let me
                  > try again.
                  > Dovetail or box ways both have the same problem when
                  > they support just one side of a heavy weight. If they
                  > are loose enough to let the weight slide down then the
                  > vert.slide is going to "sag" a little when the clamps
                  > are loosened and the jack pressure is lowered. The
                  > heavy horizontal spring is meant to do just one thing,
                  > stop this "sag" (probably as little as 10 thou.) The
                  > vertical spring is to relieve any "stickiness" of the
                  > slide caused by added jack pressure.
                  >
                  > Pat
                  >
                  >
                  > --- a1g2r3i <a1g2r3i@...> wrote:
                  >
                  > > Dear Pat
                  > > Though I tend to favour the posts that propose
                  > > ways, gibs and gib
                  > > screws; if you have your mind set on springs to keep
                  > > the parts close
                  > > together, have you thought of using valute type
                  > > springs? Valute
                  > > springs are what are used on heavy vehicles like
                  > > buldozers and such,
                  > > only use miniture valute. Perhaps wind some from 1
                  > > inch flat iron and
                  > > get it tempered. I am also wondering if I remember
                  > > valve springs that
                  > > have a valute spring inside a coil spring.
                  > > dennis mac
                  > >
                  > > --- In multimachine@yahoogroups.com, "Pat Delany"
                  > > <rigmatch@> wrote:
                  > > >
                  > > > As usual I did not explain things well.
                  > > > As the jack pressure is released, the vert. slide
                  > > leans backward to
                  > > > take up any play in the box ways. This really
                  > > offends me even though I
                  > > > am told that this is a common problem in knee
                  > > mills that have a few
                  > > > years of use on them.
                  > > > Since I planned to try springs to reduce slide
                  > > "stickiness", I thought
                  > > > I would try a second set of springs to keep the
                  > > table from "sagging"
                  > > > (slightly tilting down) as it is lowered.
                  > > > In the remote chance all this would work, think of
                  > > what we would have.
                  > > > An easily built smooth acting slide that would
                  > > stay parallel with the
                  > > > spindle at all times! This would allow milling
                  > > cuts without having to
                  > > > tighten clamp bolts! Maybe CNC would be possible.
                  > > >
                  > > > I'm probably wrong.
                  > > >
                  > > > Pat
                  > > > --- In multimachine@yahoogroups.com, "cvlac"
                  > > <cvlac0@> wrote:
                  > > > >
                  > > > > Hi Keith
                  > > > > Me too I have the same feeling, since I have not
                  > > these problems
                  > > > > because of the gibs that I have build in my
                  > > vertical slide.To one side
                  > > > > I have put a long square bronze gib that can be
                  > > adjusted with some set
                  > > > > screws, and all other screws are pushing some
                  > > small bronze discs to
                  > > > > protect the plates from their kiss.Ofcourse the
                  > > square 10X19X400
                  > > > > bronze gib was previously grind by hand .
                  > > > > For the moment I'm trying to resolve an other
                  > > MM problem.It seems
                  > > > > that the compound slide is not very well suited
                  > > for this job since it
                  > > > > is not very precise .So I'm searching in ebay to
                  > > find some low cost
                  > > > > ballscrew and linear slides to adapt them to my
                  > > equipment.
                  > > > > An other problem is that the lathe chuck is
                  > > not very useful for
                  > > > > milling since the milling arbor runs out off
                  > > center each time I'm
                  > > > > milling something hard or the cutting depth is
                  > > more than 1mm.
                  > > > > So for milling, I'm trying to find some other
                  > > solution like a low cost
                  > > > > colette chuck using the taper bush products.
                  > > > > Costas
                  > > > >
                  > > > > --- In multimachine@yahoogroups.com, keith
                  > > gutshall <drpshops@> wrote:
                  > > > > >
                  > > > > > Hello Donald
                  > > > > > I am feeling like you on the spring idea.
                  > > > > > I dont think that spring is the answer to
                  > > the problem.
                  > > > > > I think that a good set of adjustable gibs
                  > > and some runners/
                  > > > > spacers down each side of the large flat
                  > > plate.these could be 1/8 x
                  > > > > 3/4-1 in crs just screwed to the plate.
                  > > > > > The runners/ spacers are to keep the plates
                  > > from touching in the
                  > > > > middle. On a wide plate the middle if there is a
                  > > bow in ,it will
                  > > > > stick/ hangup.
                  > > > > > There should be a gib on the side to keep
                  > > any twist out of the
                  > > > > slide.
                  > > > > > There is a drawing in my photo folder
                  > > drpshops1 showing this.
                  > > > > >
                  > > > > > In my test I could move the vertical slide
                  > > up/down in less than
                  > > > > 0.0005in.I thought the small
                  > > > > > test slide worked very good made like the
                  > > drawing.
                  > > > > > The hot rolled steel took a lot of cleaning
                  > > up to work this good.
                  > > > > > Keith
                  > > > > > Donald H Locker <dhlocker@> wrote:
                  > > > > > Hi, Pat.
                  > > > > >
                  > > > > > In my interpretation, the "main block" is the
                  > > part which is
                  > > > > stationary and the
                  > > > > > "300 lb vert slide block and crossfeed" is the
                  > > movable part. The
                  > > > > springs you
                  > > > > > indicate that "hold blocks together" must
                  > > supply sufficient force
                  > > > > that they
                  > > > > > prevent the movable part from separating from
                  > > the stationary part
                  > > > > under the most
                  > > > > > extreme separating forces.
                  > > > > >
                  > > > > > As drawn, the separating forces are due to
                  > > gravity on the movable
                  > > > > part, and the
                  > > > > > minimum spring force would be ... see the
                  > > ciphering below; someone
                  > > > > else please
                  > > > > > check me.
                  > > > > >
                  > > > > > 300 lbs, approximately 9 inches from the pivot
                  > > is 225 lbf-ft; the
                  > > > > spring must
                  > > > > > provide a force that exceeds the 225 divided
                  > > by the distance from
                  > > > > the bottom of
                  > > > > > the stationary block to the spring attachment
                  > > (in ft). The force
                  > > > > applied by a
                  > > > > > spring is equal to its "rate" (should be
                  > > specified in the
                  > > > > documentation for it,
                  > > > > > or can be measured) multiplied by its
                  > > deflection, plus any initial
                  > > > set.
                  > > > > >
                  > > > > > A spring with a rate of 500 lb/in, with an
                  > > intial set of 50 lbs
                  > > > > would require an
                  > > > > > installed length of 3/8 inch if the attachment
                  > > were one foot above
                  > > > > the bottom of
                  > > > > > the stationary block. More or less. (225 lbs
                  > > needed - 50 lbs initial
                  > > > > set) =
                  > > > > > 175 lbs needed by stretching spring; (175
                  > > lbs)/(500 lbs/inch) = 0.35
                  > > > > inches.
                  > > > > > Round up to the nearest fraction.)
                  > > > > >
                  > > > > > In my opinion, rather than a spring, a set of
                  > > gibs or guide-bars
                  > > > > would be
                  > > > > > better. These are essentially springs with
                  > > _very_ high spring rates
                  > > > > and would
                  > > > > > be more reliable.
                  > > > > >
                  > > > > > HTH,
                  > > > > > Donald.
                  > > > > >
                  > > > > > Pat Delany wrote:
                  > > > > > > In the photo folder "Vert slide springs", I
                  > > put a crude drawing
                  > > > of an
                  > > > > > > MM with some vert slide springs added. I am
                  > > going to try 2 mower
                  > > > deck
                  > > > > > > springs to pull the block down but I do now
                  > > know what kind of
                  > > spring
                  > > > > > > to use to hold the blocks together when jack
                  > > pressure is
                  > > released. I
                  > > > > > > guess this is a simple engineering problem
                  > > but I do not have a
                  > > clue
                  > > > > > > about solving it.
                  > > > > > >
                  > > > > > > Pat
                  > > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > >
                  > > > > > Deep Run Portage
                  > > > > > Back Shop
                  > >
                  > === message truncated ===
                  >
                  >
                  >
                  >
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                • Pat Delany
                  You are quite right. An upcoming test will use an adjustable jacking point that is underneath the small block. Pat
                  Message 8 of 21 , May 12, 2008
                  • 0 Attachment
                    You are quite right. An upcoming test will use an adjustable jacking
                    point that is underneath the small block.

                    Pat

                    --- In multimachine@yahoogroups.com, "jimyjak1" <jimyjak1@...> wrote:
                    >
                    > Hi Pat and All
                    > If the jack is centered under the weight there will be no sag and no
                    > need for springs. You could even move the jack just a bit forward to
                    > make the weight lean into the big block. Never place the jack close to
                    > the big block as this will cause sag and undue ware on the ways. Just
                    > the thoughts of an old jack of all trades.
                    > jimyjack
                    >
                    > --- In multimachine@yahoogroups.com, Pat Delany <rigmatch@> wrote:
                    > >
                    > > I have really screwed up explaining this idea! Let me
                    > > try again.
                    > > Dovetail or box ways both have the same problem when
                    > > they support just one side of a heavy weight. If they
                    > > are loose enough to let the weight slide down then the
                    > > vert.slide is going to "sag" a little when the clamps
                    > > are loosened and the jack pressure is lowered. The
                    > > heavy horizontal spring is meant to do just one thing,
                    > > stop this "sag" (probably as little as 10 thou.) The
                    > > vertical spring is to relieve any "stickiness" of the
                    > > slide caused by added jack pressure.
                    > >
                    > > Pat
                    > >
                    > >
                    > > --- a1g2r3i <a1g2r3i@> wrote:
                    > >
                    > > > Dear Pat
                    > > > Though I tend to favour the posts that propose
                    > > > ways, gibs and gib
                    > > > screws; if you have your mind set on springs to keep
                    > > > the parts close
                    > > > together, have you thought of using valute type
                    > > > springs? Valute
                    > > > springs are what are used on heavy vehicles like
                    > > > buldozers and such,
                    > > > only use miniture valute. Perhaps wind some from 1
                    > > > inch flat iron and
                    > > > get it tempered. I am also wondering if I remember
                    > > > valve springs that
                    > > > have a valute spring inside a coil spring.
                    > > > dennis mac
                    > > >
                    > > > --- In multimachine@yahoogroups.com, "Pat Delany"
                    > > > <rigmatch@> wrote:
                    > > > >
                    > > > > As usual I did not explain things well.
                    > > > > As the jack pressure is released, the vert. slide
                    > > > leans backward to
                    > > > > take up any play in the box ways. This really
                    > > > offends me even though I
                    > > > > am told that this is a common problem in knee
                    > > > mills that have a few
                    > > > > years of use on them.
                    > > > > Since I planned to try springs to reduce slide
                    > > > "stickiness", I thought
                    > > > > I would try a second set of springs to keep the
                    > > > table from "sagging"
                    > > > > (slightly tilting down) as it is lowered.
                    > > > > In the remote chance all this would work, think of
                    > > > what we would have.
                    > > > > An easily built smooth acting slide that would
                    > > > stay parallel with the
                    > > > > spindle at all times! This would allow milling
                    > > > cuts without having to
                    > > > > tighten clamp bolts! Maybe CNC would be possible.
                    > > > >
                    > > > > I'm probably wrong.
                    > > > >
                    > > > > Pat
                    > > > > --- In multimachine@yahoogroups.com, "cvlac"
                    > > > <cvlac0@> wrote:
                    > > > > >
                    > > > > > Hi Keith
                    > > > > > Me too I have the same feeling, since I have not
                    > > > these problems
                    > > > > > because of the gibs that I have build in my
                    > > > vertical slide.To one side
                    > > > > > I have put a long square bronze gib that can be
                    > > > adjusted with some set
                    > > > > > screws, and all other screws are pushing some
                    > > > small bronze discs to
                    > > > > > protect the plates from their kiss.Ofcourse the
                    > > > square 10X19X400
                    > > > > > bronze gib was previously grind by hand .
                    > > > > > For the moment I'm trying to resolve an other
                    > > > MM problem.It seems
                    > > > > > that the compound slide is not very well suited
                    > > > for this job since it
                    > > > > > is not very precise .So I'm searching in ebay to
                    > > > find some low cost
                    > > > > > ballscrew and linear slides to adapt them to my
                    > > > equipment.
                    > > > > > An other problem is that the lathe chuck is
                    > > > not very useful for
                    > > > > > milling since the milling arbor runs out off
                    > > > center each time I'm
                    > > > > > milling something hard or the cutting depth is
                    > > > more than 1mm.
                    > > > > > So for milling, I'm trying to find some other
                    > > > solution like a low cost
                    > > > > > colette chuck using the taper bush products.
                    > > > > > Costas
                    > > > > >
                    > > > > > --- In multimachine@yahoogroups.com, keith
                    > > > gutshall <drpshops@> wrote:
                    > > > > > >
                    > > > > > > Hello Donald
                    > > > > > > I am feeling like you on the spring idea.
                    > > > > > > I dont think that spring is the answer to
                    > > > the problem.
                    > > > > > > I think that a good set of adjustable gibs
                    > > > and some runners/
                    > > > > > spacers down each side of the large flat
                    > > > plate.these could be 1/8 x
                    > > > > > 3/4-1 in crs just screwed to the plate.
                    > > > > > > The runners/ spacers are to keep the plates
                    > > > from touching in the
                    > > > > > middle. On a wide plate the middle if there is a
                    > > > bow in ,it will
                    > > > > > stick/ hangup.
                    > > > > > > There should be a gib on the side to keep
                    > > > any twist out of the
                    > > > > > slide.
                    > > > > > > There is a drawing in my photo folder
                    > > > drpshops1 showing this.
                    > > > > > >
                    > > > > > > In my test I could move the vertical slide
                    > > > up/down in less than
                    > > > > > 0.0005in.I thought the small
                    > > > > > > test slide worked very good made like the
                    > > > drawing.
                    > > > > > > The hot rolled steel took a lot of cleaning
                    > > > up to work this good.
                    > > > > > > Keith
                    > > > > > > Donald H Locker <dhlocker@> wrote:
                    > > > > > > Hi, Pat.
                    > > > > > >
                    > > > > > > In my interpretation, the "main block" is the
                    > > > part which is
                    > > > > > stationary and the
                    > > > > > > "300 lb vert slide block and crossfeed" is the
                    > > > movable part. The
                    > > > > > springs you
                    > > > > > > indicate that "hold blocks together" must
                    > > > supply sufficient force
                    > > > > > that they
                    > > > > > > prevent the movable part from separating from
                    > > > the stationary part
                    > > > > > under the most
                    > > > > > > extreme separating forces.
                    > > > > > >
                    > > > > > > As drawn, the separating forces are due to
                    > > > gravity on the movable
                    > > > > > part, and the
                    > > > > > > minimum spring force would be ... see the
                    > > > ciphering below; someone
                    > > > > > else please
                    > > > > > > check me.
                    > > > > > >
                    > > > > > > 300 lbs, approximately 9 inches from the pivot
                    > > > is 225 lbf-ft; the
                    > > > > > spring must
                    > > > > > > provide a force that exceeds the 225 divided
                    > > > by the distance from
                    > > > > > the bottom of
                    > > > > > > the stationary block to the spring attachment
                    > > > (in ft). The force
                    > > > > > applied by a
                    > > > > > > spring is equal to its "rate" (should be
                    > > > specified in the
                    > > > > > documentation for it,
                    > > > > > > or can be measured) multiplied by its
                    > > > deflection, plus any initial
                    > > > > set.
                    > > > > > >
                    > > > > > > A spring with a rate of 500 lb/in, with an
                    > > > intial set of 50 lbs
                    > > > > > would require an
                    > > > > > > installed length of 3/8 inch if the attachment
                    > > > were one foot above
                    > > > > > the bottom of
                    > > > > > > the stationary block. More or less. (225 lbs
                    > > > needed - 50 lbs initial
                    > > > > > set) =
                    > > > > > > 175 lbs needed by stretching spring; (175
                    > > > lbs)/(500 lbs/inch) = 0.35
                    > > > > > inches.
                    > > > > > > Round up to the nearest fraction.)
                    > > > > > >
                    > > > > > > In my opinion, rather than a spring, a set of
                    > > > gibs or guide-bars
                    > > > > > would be
                    > > > > > > better. These are essentially springs with
                    > > > _very_ high spring rates
                    > > > > > and would
                    > > > > > > be more reliable.
                    > > > > > >
                    > > > > > > HTH,
                    > > > > > > Donald.
                    > > > > > >
                    > > > > > > Pat Delany wrote:
                    > > > > > > > In the photo folder "Vert slide springs", I
                    > > > put a crude drawing
                    > > > > of an
                    > > > > > > > MM with some vert slide springs added. I am
                    > > > going to try 2 mower
                    > > > > deck
                    > > > > > > > springs to pull the block down but I do now
                    > > > know what kind of
                    > > > spring
                    > > > > > > > to use to hold the blocks together when jack
                    > > > pressure is
                    > > > released. I
                    > > > > > > > guess this is a simple engineering problem
                    > > > but I do not have a
                    > > > clue
                    > > > > > > > about solving it.
                    > > > > > > >
                    > > > > > > > Pat
                    > > > > > > >
                    > > > > > >
                    > > > > > >
                    > > > > > >
                    > > > > > >
                    > > > > > >
                    > > > > > > Deep Run Portage
                    > > > > > > Back Shop
                    > > >
                    > > === message truncated ===
                    > >
                    > >
                    > >
                    > >
                    >
                    ____________________________________________________________________________________
                    > > Be a better friend, newshound, and
                    > > know-it-all with Yahoo! Mobile. Try it now.
                    > http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
                    > >
                    >
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