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Was: Lathe Spindle Now: Moving heavy objects

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  • Shannon DeWolfe
    Howard, If you still need to move that house, talk to the man who has this site: http://www.theforgottentechnology.com/ Be sure to see the pole barn he moved
    Message 1 of 28 , Jan 5, 2013
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      Howard,

      If you still need to move that house, talk to the man who has this site:

      http://www.theforgottentechnology.com/

      Be sure to see the pole barn he moved on page two.

      Regards,

      Mr. Shannon DeWolfe
      --I've taken to using Mr. because my name misleads folks on the WWW. I am a 56 year old fat man.

      On 1/5/2013 2:51 PM, StoneTool wrote:
      >
      > Pierre:
      > At one time I had intentions of moving a small house in this way a
      > short distance.
      >
    • jacot
      Ì know a mercury mirror of 4 meter on air bearing here in quebec city astronomy department Jack 47’n 71’”w Exactly right about how it works. You might
      Message 2 of 28 , Jan 5, 2013
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        Ì know a mercury mirror of 4 meter on  air bearing here in quebec city astronomy department

         

        Jack 47’n 71’”w

         




        Exactly right about how it works.  You might be surprised on how heavy loads are carried by air bearings though...  His little swiss lathe was smaller than my sherline, and probably never took heavy loads, but there are massive machines using air bearings.

        A little reading on the topic is very interesting.  At some point I want to put a bunch of heavy tools on bases that float off the concrete shop floor when air is applied, but sit solidly when the hose comes off.

         

        On Sat, Jan 5, 2013 at 10:37 AM, StoneTool <owly@...> wrote:

         

        Pierre:
            I presume the air entered the bearing clearance area from numerous small holes, and that the bearing clearance was extremely small, and furthermore that the air leakage probably wasn't all that great.   I superb idea.  The surface area of the spindle and the pressure of the air would be important related to the load. It probably wasn't designed for really heavy work.

                                                                                    Howard





        On 01/05/2013 09:43 AM, Pierre Coueffin wrote:

        I used to work with a guy who owned a company that had a swiss made tool-room lathe that had air-bearings in the spindle...  He showed me how they worked one time, by hooking up a line from the compressor to the headstock of the lathe, which made the spindle turn freely on a few micron cushion of air.  He spun the spindle up with his finger tip (the machine was unplugged) and we went and had our meeting.  We came out half an hour later and the spindle was still slowly turning.

        Essentially they are a fluid bearing, like a sintered bronze bushing, but the working fluid is air, forced into the very narrow gap under high pressure.  Any force that tilts the shaft in the gap makes the gap narrower on one side than the other.  This increases the amount of air pressure on that side rapidly, which re-centers the shaft.

        http://en.wikipedia.org/wiki/Fluid_bearing

        Anyone who has ever played air-hockey will be familiar with the related linear version of this bearing.

         

        If a person had built a multimachine capable of the required precision, and they had access to large volumes of compressed air, it would be a neat upgrade to make a cartridge spindle for their multimachine using an air-bearing setup...  It would be quite straight forward to create a thrust bearing and a radial bearing surface, and combine them into one spindle.  The precision fit required is finicky, but could probably be achievable by hand lapping or scraping if you had the ability to measure your results.

         

         




      • David G. LeVine
        ... Actually, my memory is a bit different. Air bearings CAN require a lot of volume (look at one being used to move heavy equipment on a floor), but for
        Message 3 of 28 , Jan 5, 2013
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          On 01/05/2013 03:21 PM, Shannon DeWolfe wrote:
          Keep in mind that air bearings require high pressures and large volume. 
          I have spent a lot, make that, A LOT of time researching ways to 
          compress air. It takes horsepower. More than 150 lbs./in.² at industrial 
          volume takes A LOT of horsepower. Also, air bearings do not like oil, 
          water, nor dirt.

          Actually, my memory is a bit different.  Air bearings CAN require a lot of volume (look at one being used to move heavy equipment on a floor), but for tight clearance loads (like a good spindle), the airflow is related to the clearance.  A very tight system (say 0.00005" - that is 50 MILLIONTHS of an inch) will have low leakage and will probably not be able to be turned without air.  A loose system (say 0.005", 5 thousandths of an inch) will need a lot of flow to work.

          Skirts are often used with very loose fitting setups (like the machine on a concrete floor.) 

          So yes and no, air bearings CAN need a lot of flow, but they don't have to.

          Dave  8{)

          --


          "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

          Mohandus Ghandi, An Autobiography, Page 446.
        • StoneTool
          Thanks: Great site! The outrageously unconventional idea of moving it on a cushion of air was the driver behind the proposed project. At this point, I
          Message 4 of 28 , Jan 5, 2013
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            Thanks:
            Great site! The outrageously unconventional idea of moving it on
            a cushion of air was the driver behind the proposed project. At this
            point, I don't foresee ever moving it intact, as any location I would
            now move it to would be too distant. This house was built near the
            turn of the century out of green pine logs that were flattened on two
            sides using an adze and a broad axe. The flattened sides were inside
            and out. The outside was covered with sheet metal not long after it was
            built, and the interior was covered with beaver board......... something
            most folks have never heard of these days. A kind of pressed board like
            very heavy liner-board (shoe box material) about a quarter inch thick.
            Beneath the beaver board they insulated with newspaper. The newspaper
            dates from the late 1800's and is from California mostly (bay area).
            It's been sealed from light for many years and though crumbly is
            readable until it crumbles. The logs were fresh, and in many places
            the paper adhered to the freshly hewn surfaces, leaving readable
            articles on the surface of the logs. Everything from period
            advertizing to political commentary to stories about hangings and
            crimes, etc. It's a history book, but the only parts that can be saved
            are the parts stuck to the logs. My plan was to use epoxy clearcoat
            such as "Super Glaze", to seal the paper to the log where it was stuck
            and to provide a clear protective layer, and then expose the logs on the
            interior, preserving hand hewn logs with readable snippets of ancient
            newspaper for a truly unique effect.
            As it currently stands, I will never move the house..... which is
            an old wreck, or I will strip the interior and preserve the newspapers,
            and dismantle it carefully and transport it a considerable distance and
            reassemble it on site. The sheet metal on the exterior has left the
            logs in very good shape along with our extremely dry climate (Eastern
            Montana).


            Howard


            On 01/05/2013 01:27 PM, Shannon DeWolfe wrote:
            > Howard,
            >
            > If you still need to move that house, talk to the man who has this site:
            >
            > http://www.theforgottentechnology.com/
            >
            > Be sure to see the pole barn he moved on page two.
            >
            > Regards,
            >
            > Mr. Shannon DeWolfe
            > --I've taken to using Mr. because my name misleads folks on the WWW. I am a 56 year old fat man.
            >
            > On 1/5/2013 2:51 PM, StoneTool wrote:
            >> Pierre:
            >> At one time I had intentions of moving a small house in this way a
            >> short distance.
            >>
            >
            >
            > ------------------------------------
            >
            > -------------
            > We have a sister site for files and pictures dedicated to concrete machine framed machine tools. You will find a great deal of information about concrete based machines and the inventor of the concrete frame lathe, Lucian Ingraham Yeomans. Go to http://groups.yahoo.com/group/Multimachine-Concrete-Machine-Tools/
            >
            > Also visit the Joseph V. Romig group for even more concrete tool construction, shop notes, stories, and wisdom from the early 20th Century.
            > http://tech.groups.yahoo.com/group/romig_designs/
            > -------------Yahoo! Groups Links
            >
            >
            >
            >
          • StoneTool
            David Clearances such as you are talking about are entirely impractical. The slightest thermal changes cause interference and galling and seizure instantly.
            Message 5 of 28 , Jan 5, 2013
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              David
                  Clearances such as you are talking about are entirely impractical.  The slightest thermal changes cause interference and galling and seizure instantly.  I've played with some extremely tight clearances........ down under .001 and even a light film of oil will prevent things from slipping together.   You can achieve some incredibly tight tolerances with a pin hone (wrist pin hone).  Fuel injection parts are sealed entirely by clearances that allow the part to move but the oil cannot pass through.  Hydraulic valves, likewise do NOT have seals, and depend entirely on tolerances.  They are nowhere near the numbers you are talking about.........

                  That said, I agree entirely that clearance is the critical factor as far as maximizing support for a given airflow.   Sealing however is counter productive.  You have to have flow to get the support.  There is an optimal clearance and an optimal airflow & pressure.  If your clearance is too close, the pressure must be significantly higher.   Pressure (in psi) * Flow (cubic feet per minute) / 12790 = Horsepower..........    Clearly increasing pressure or increasing flow has an equal effect on horsepower.   Tighten your clearances and you need more pressure.......... loosen your clearances and you need more flow (within reason), the result within a reasonable range is going to be a roughly equal horsepower requirement on your compressor.

                                                                                      Howard

              On 01/05/2013 09:18 PM, David G. LeVine wrote:
              On 01/05/2013 03:21 PM, Shannon DeWolfe wrote:
              Keep in mind that air bearings require high pressures and large volume. 
              I have spent a lot, make that, A LOT of time researching ways to 
              compress air. It takes horsepower. More than 150 lbs./in.² at industrial 
              volume takes A LOT of horsepower. Also, air bearings do not like oil, 
              water, nor dirt.

              Actually, my memory is a bit different.  Air bearings CAN require a lot of volume (look at one being used to move heavy equipment on a floor), but for tight clearance loads (like a good spindle), the airflow is related to the clearance.  A very tight system (say 0.00005" - that is 50 MILLIONTHS of an inch) will have low leakage and will probably not be able to be turned without air.  A loose system (say 0.005", 5 thousandths of an inch) will need a lot of flow to work.

              Skirts are often used with very loose fitting setups (like the machine on a concrete floor.) 

              So yes and no, air bearings CAN need a lot of flow, but they don't have to.

              Dave  8{)

              --


              "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

              Mohandus Ghandi, An Autobiography, Page 446.

            • jacot
              A bit off topic But Any of you have made chrismes ornament un wood or brass or allu Jacxk 47’n 71’LW On 01/05/2013 03:21 PM, Shannon DeWolfe wrote: Keep
              Message 6 of 28 , Jan 6, 2013
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                A  bit off topic

                But

                Any of you have made  chrismes ornament un wood or brass or allu

                 

                Jacxk 47’n 71’LW




                On 01/05/2013 03:21 PM, Shannon DeWolfe wrote:

                Keep in mind that air bearings require high pressures and large volume. 
                I have spent a lot, make that, A LOT of time researching ways to 
                compress air. It takes horsepower. More than 150 lbs./in.² at industrial 
                volume takes A LOT of horsepower. Also, air bearings do not like oil, 
                water, nor dirt.


                Actually, my memory is a bit different.  Air bearings CAN require a lot of volume (look at one being used to move heavy equipment on a floor), but for tight clearance loads (like a good spindle), the airflow is related to the clearance.  A very tight system (say 0.00005" - that is 50 MILLIONTHS of an inch) will have low leakage and will probably not be able to be turned without air.  A loose system (say 0.005", 5 thousandths of an inch) will need a lot of flow to work.

                Skirts are often used with very loose fitting setups (like the machine on a concrete floor.) 

                So yes and no, air bearings CAN need a lot of flow, but they don't have to.

                Dave  8{)

                --


                "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

                Mohandus Ghandi, An Autobiography, Page 446.




              • David G. LeVine
                ... Howard, New Way in its application guide at ... Four standard cubic feet per HOUR is not a lot of air, that is about 1/60 of the output of a common 2 HP
                Message 7 of 28 , Jan 6, 2013
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                  On 01/06/2013 12:34 AM, StoneTool wrote:

                  David
                      Clearances such as you are talking about are entirely impractical.  The slightest thermal changes cause interference and galling and seizure instantly.  I've played with some extremely tight clearances........ down under .001 and even a light film of oil will prevent things from slipping together.   You can achieve some incredibly tight tolerances with a pin hone (wrist pin hone).  Fuel injection parts are sealed entirely by clearances that allow the part to move but the oil cannot pass through.  Hydraulic valves, likewise do NOT have seals, and depend entirely on tolerances.  They are nowhere near the numbers you are talking about.........

                      That said, I agree entirely that clearance is the critical factor as far as maximizing support for a given airflow.   Sealing however is counter productive.  You have to have flow to get the support.  There is an optimal clearance and an optimal airflow & pressure.  If your clearance is too close, the pressure must be significantly higher.   Pressure (in psi) * Flow (cubic feet per minute) / 12790 = Horsepower..........    Clearly increasing pressure or increasing flow has an equal effect on horsepower.   Tighten your clearances and you need more pressure.......... loosen your clearances and you need more flow (within reason), the result within a reasonable range is going to be a roughly equal horsepower requirement on your compressor.

                                                                                          Howard

                  Howard,

                  New Way in its application guide at http://www.newwayairbearings.com/design/application-guide says:

                  Airflow through a bearing gap is quite sensitive to the gap; in fact it is a cube function of the gap. As
                  an example of two inch diameter bearing with 75 pounds of load would consume 4 standard cubic
                  feet per hour at 200 micro inches of lift. For this bearing to carry the same load at 400 micro inches
                  of lift 64 standard cubic feet per hour of air would be required. It can easily be seen that small gaps
                  keep restriction high and hence reduce flow and power requirements. Less airflow means less air
                  needs to be compressed cleaned and dried reducing cost of ownership issues.

                  Four standard cubic feet per HOUR is not a lot of air, that is about 1/60 of the output of a common 2 HP compressor.  In fact, a 1/8 HP Harbor Freight compressor runs 30 CFH at 20 PSI (0.5 CFM), less at higher pressure, and this is not a high end compressor.  They are talking 200 micro inches, 0.0002" in this example, depending on finish that may be way too big a gap.

                  Most air bearings these days will not allow one to move the supported structure without damage without air pressure.

                  It sounds like technology has changed quite a bit since your experiences.

                  Dave  8{)


                  --


                  "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

                  Mohandus Ghandi, An Autobiography, Page 446.
                • StoneTool
                  David: I would suggest that you try assembling something with that sort of clearance............... Howard
                  Message 8 of 28 , Jan 6, 2013
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                    David:
                        I would suggest that you try assembling something with that sort of clearance...............

                                                                                                Howard

                    On 01/06/2013 10:10 AM, David G. LeVine wrote:
                    On 01/06/2013 12:34 AM, StoneTool wrote:

                    David
                        Clearances such as you are talking about are entirely impractical.  The slightest thermal changes cause interference and galling and seizure instantly.  I've played with some extremely tight clearances........ down under .001 and even a light film of oil will prevent things from slipping together.   You can achieve some incredibly tight tolerances with a pin hone (wrist pin hone).  Fuel injection parts are sealed entirely by clearances that allow the part to move but the oil cannot pass through.  Hydraulic valves, likewise do NOT have seals, and depend entirely on tolerances.  They are nowhere near the numbers you are talking about.........

                        That said, I agree entirely that clearance is the critical factor as far as maximizing support for a given airflow.   Sealing however is counter productive.  You have to have flow to get the support.  There is an optimal clearance and an optimal airflow & pressure.  If your clearance is too close, the pressure must be significantly higher.   Pressure (in psi) * Flow (cubic feet per minute) / 12790 = Horsepower..........    Clearly increasing pressure or increasing flow has an equal effect on horsepower.   Tighten your clearances and you need more pressure.......... loosen your clearances and you need more flow (within reason), the result within a reasonable range is going to be a roughly equal horsepower requirement on your compressor.

                                                                                            Howard

                    Howard,

                    New Way in its application guide at http://www.newwayairbearings.com/design/application-guide says:

                    Airflow through a bearing gap is quite sensitive to the gap; in fact it is a cube function of the gap. As
                    an example of two inch diameter bearing with 75 pounds of load would consume 4 standard cubic
                    feet per hour at 200 micro inches of lift. For this bearing to carry the same load at 400 micro inches
                    of lift 64 standard cubic feet per hour of air would be required. It can easily be seen that small gaps
                    keep restriction high and hence reduce flow and power requirements. Less airflow means less air
                    needs to be compressed cleaned and dried reducing cost of ownership issues.

                    Four standard cubic feet per HOUR is not a lot of air, that is about 1/60 of the output of a common 2 HP compressor.  In fact, a 1/8 HP Harbor Freight compressor runs 30 CFH at 20 PSI (0.5 CFM), less at higher pressure, and this is not a high end compressor.  They are talking 200 micro inches, 0.0002" in this example, depending on finish that may be way too big a gap.

                    Most air bearings these days will not allow one to move the supported structure without damage without air pressure.

                    It sounds like technology has changed quite a bit since your experiences.

                    Dave  8{)


                    --


                    "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

                    Mohandus Ghandi, An Autobiography, Page 446.

                  • David G. LeVine
                    ... Back in the 1970s I did, it was tricky, but not impossible (and that was many moons ago!) It took a lot of jigging and pressure, but it worked. The
                    Message 9 of 28 , Jan 6, 2013
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                      On 01/06/2013 01:38 PM, StoneTool wrote:

                      David:
                          I would suggest that you try assembling something with that sort of clearance...............

                                                                                                  Howard

                      Back in the 1970s I did, it was tricky, but not impossible (and that was many moons ago!)  It took a lot of jigging and pressure, but it worked.  The surface cleanliness was simply incredible (I worked in an optical encoder and metrology company.) 

                      Air bearings are often sintered porous graphite these days (like a fish tank stone) and MUST be assembled with pressure on or they won't go.  Put the bearing in the housing with o-rings to support and seal it, apply 90 PSI, press the shaft into place.  The shaft is self aligning, there can be no steps as the shaft tapers to the correct diameter, but if the shaft starts at .002-.005" undersize with a conic section leading to the bearing surface, that is okay.  It CAN NOT be assembled without air pressure, it just jams and galls.  The stiffness is amazing -- 2 million pounds per inch!

                      The trick is the powdered graphite bearing, even with clearances of 1/4" (that is HUGE), the bearing has enough resistance to flow that the pressure can be maintained.

                      Read the New Way manual, the world has changed.

                      Dave  8{)

                      --


                      "Among the many misdeeds of British rule in India, history will look upon the Act of depriving a whole nation of arms as the blackest."

                      Mohandus Ghandi, An Autobiography, Page 446.
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