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RE: [TeslaTurbine] Shafted

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  • Meagher, Mike
    ... Long time lurker, first time poster... I ll echo Jim s comments about Harbor Freight or Northern Tool as a source for small metalworking lathes. I ve got
    Message 1 of 22 , Aug 22 7:47 AM
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      >
      > Thanks Jim, I'm creating a TT with CD ROMs with maximum
      > speeds around 10k rpm. I was wanting light weight and
      > low cost. The diameter shaft and length of shaft give
      > really good strengths for the low speed.
      > In the future I'll have harder/stronger shafts.
      >
      > Mike Passerotti
      >

      Long time lurker, first time poster...

      I'll echo Jim's comments about Harbor Freight or Northern Tool as a source for small metalworking lathes. I've got one of the HF 7x10 Asian lathes, and it is surprising just how versatile that little machine is. There is a discussion group on Yahoo devoted to the 7x10 and 7x12 lathes (http://groups.yahoo.com/group/7x10minilate), in addition to their small milling machine cousins.

      If you are interested in these small machines, try http://www.mini-lathe.com There are comparisons of the lathes from different sources (Harbor Freight, Grizzly and Homier) in addition to other useful information about these machines. I have no connection with the web site or manufacturers/marketers of these machines.

      Back on the TT topic, I've got four dead hard drives that would be (it seems to me) perfect donors for components, particularly the rotors (the platters are extremely smooth). Has anyone built a TT using hard drive platters for the rotors? If so, which approach would be better, drilling holes in the rotors or making a hollow shaft?

      Thanks

      Mike
      Carrollton, TX
    • Ian Main
      One thing I noticed when playing with CD s is that they have an outer ridge on them that is thicker than the rest of the CD. I don t think that is very ideal
      Message 2 of 22 , Aug 22 10:16 AM
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        One thing I noticed when playing with CD's is that they have an outer
        ridge on them that is thicker than the rest of the CD. I don't think
        that is very ideal for the TT as you want uniform runner spacing and
        it's hard to even tell what the spacing would be at the center with
        that ridge in the way.

        Fine for playing with but not ideal I don't think.

        Ian

        On Thu, Aug 22, 2002 at 10:32:23AM -0400, Mike Passerotti wrote:
        > Did I mention my budget? Very small in relationship to a sunflower seed.
        > The CDs can handle the rpm design because I'm designing for the CD strength,
        > not beyond. I do have a great big wish list. For now, I have to get one
        > built, preferebly see through so I can run experiments on improvement.
        >
        >
        > Mike Passerotti
        >
        > -----Original Message-----
        > From: McGalliard, Frederick B [mailto:frederick.b.mcgalliard@...]
        > Sent: Thursday, August 22, 2002 10:17 AM
        > To: 'TeslaTurbine@yahoogroups.com'
        > Subject: RE: [TeslaTurbine] Shafted
        >
        >
        > With material as brittle as the disks, the more keys the better. If you are
        > really going to go to much effort, don't you think it might be worth it to
        > get something that will be a bit more robust than a CD?
        >
        > -----Original Message-----
        > From: Mike Passerotti [mailto:mike.passerotti@...]
        > Sent: Thursday, August 22, 2002 6:25 AM
        > To: 'TeslaTurbine@yahoogroups.com'
        > Subject: RE: [TeslaTurbine] Shafted
        >
        >
        >
        > Keyslot on the shaft and keyslot on the cd hub, and a key. The shaft will
        > have one shoulder for the cd hub on one side. The cd washers will be cd
        > hubs cut down to just reaching the inside edge of the exhaust ports. The
        > other end of the shaft will have a threaded nut that will push on a washer
        > (slotted for the key also). The washer will compress the cd hubs against
        > the stationary shoulder. I'll setup the rotation and the threads so that
        > the nut won't come off while in operation. This is a low power application
        > so the key can be small square aluminum bar stock. If ballance is needed
        > I'll have to use a second key opposing the first key. Dang, that sentence
        > sounded too much like a patent description. I've written two mechanical
        > patents for an employer. What do you think about one versus two keys?
        >
        > I have access to a 50 W laser machine to cut my exhaust ports, rivet holes,
        > washers and key slots on the CDs.
        >
        > I'll be removing the gold layer on the CDs to prevent removal during
        > operation. When rubbing the gold layer off CDs with my fingers, I made a
        > mental note on just how easy it is to destroy CDs. Be careful with them.
        >
        > Here is an ascii profile of the shaft:
        >
        > _______
        > ___-| |-------------++---------____
        > 1 2 3 4 5 6 7 8 9
        > 1 bearing
        > 2 bearing shoulder
        > 3 exhaust area
        > 4 CD hub stationary shoulder
        > 5 CD hub / disc pack (key slotted)
        > 6 threaded for dick back compression against a washer
        > 7 exhaust area
        > 8 bearing shoulder
        > 9 bearing
        >
        > Mike Passerotti
        >
        > -----Original Message-----
        > From: abnengineering@... [mailto:abnengineering@...]
        > Sent: Thursday, August 22, 2002 1:49 AM
        > To: TeslaTurbine@yahoogroups.com
        > Subject: RE: [TeslaTurbine] Shafted
        >
        >
        > How are you going to mount the cd's to the shaft?
        >
        > Mike Passerotti <mike.passerotti@...> wrote:
        >
        > >I want an aluminum shaft for my CD turbine. Anyone able to lend a hand?
        > >Its a small shaft, but I don't have access to a metal lathe. Any ideas on
        > >obtaining a small metal lathe?
        > >
        > >
        > >Mike Passerotti
        > >
        > >
        > >
        > >
        > >
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      • Mike Passerotti
        Not Ideal to be sure. The edge on my CDs are uniform with the majority of the CD. The hub has a ridge just inside the recording media. That ridge is not
        Message 3 of 22 , Aug 22 11:05 AM
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          Not Ideal to be sure. The edge on my CDs are uniform with the majority of
          the CD. The hub has a ridge just inside the recording media. That ridge is
          not guarenteed to be the same from vendor to vendor. Best to use all the
          same CD manufacture and product for uniformity. If you'll notice, the ridge
          on one side is a trough on the other side. The CDs will have a space
          between them when stacked. Its a very small space. I'll be cutting the
          hubs out of CDs in order to make the washers that make the spacing between
          disks. The hubs I cut out will include the ridge for wider spacing and not
          include the ridge for narrower spacing.

          And yes, I'm building my first TT and playing with it. I'm not expecting a
          high performance TT but one I can make measurements on for design
          improvements without high cost of replacing parts. Plus, the clear case and
          clear discs will enable internal viewing of the flow.


          Mike Passerotti

          -----Original Message-----
          From: Ian Main [mailto:ian3@...]
          Sent: Thursday, August 22, 2002 1:17 PM
          To: TeslaTurbine@yahoogroups.com
          Subject: Re: [TeslaTurbine] Shafted


          One thing I noticed when playing with CD's is that they have an outer
          ridge on them that is thicker than the rest of the CD. I don't think
          that is very ideal for the TT as you want uniform runner spacing and
          it's hard to even tell what the spacing would be at the center with
          that ridge in the way.

          Fine for playing with but not ideal I don't think.

          Ian

          On Thu, Aug 22, 2002 at 10:32:23AM -0400, Mike Passerotti wrote:
          > Did I mention my budget? Very small in relationship to a sunflower seed.
          > The CDs can handle the rpm design because I'm designing for the CD
          strength,
          > not beyond. I do have a great big wish list. For now, I have to get one
          > built, preferebly see through so I can run experiments on improvement.
          >
          >
          > Mike Passerotti
          >
          > -----Original Message-----
          > From: McGalliard, Frederick B [mailto:frederick.b.mcgalliard@...]
          > Sent: Thursday, August 22, 2002 10:17 AM
          > To: 'TeslaTurbine@yahoogroups.com'
          > Subject: RE: [TeslaTurbine] Shafted
          >
          >
          > With material as brittle as the disks, the more keys the better. If you
          are
          > really going to go to much effort, don't you think it might be worth it to
          > get something that will be a bit more robust than a CD?
          >
          > -----Original Message-----
          > From: Mike Passerotti [mailto:mike.passerotti@...]
          > Sent: Thursday, August 22, 2002 6:25 AM
          > To: 'TeslaTurbine@yahoogroups.com'
          > Subject: RE: [TeslaTurbine] Shafted
          >
          >
          >
          > Keyslot on the shaft and keyslot on the cd hub, and a key. The shaft will
          > have one shoulder for the cd hub on one side. The cd washers will be cd
          > hubs cut down to just reaching the inside edge of the exhaust ports. The
          > other end of the shaft will have a threaded nut that will push on a washer
          > (slotted for the key also). The washer will compress the cd hubs against
          > the stationary shoulder. I'll setup the rotation and the threads so that
          > the nut won't come off while in operation. This is a low power
          application
          > so the key can be small square aluminum bar stock. If ballance is needed
          > I'll have to use a second key opposing the first key. Dang, that sentence
          > sounded too much like a patent description. I've written two mechanical
          > patents for an employer. What do you think about one versus two keys?
          >
          > I have access to a 50 W laser machine to cut my exhaust ports, rivet
          holes,
          > washers and key slots on the CDs.
          >
          > I'll be removing the gold layer on the CDs to prevent removal during
          > operation. When rubbing the gold layer off CDs with my fingers, I made a
          > mental note on just how easy it is to destroy CDs. Be careful with them.
          >
          > Here is an ascii profile of the shaft:
          >
          > _______
          > ___-| |-------------++---------____
          > 1 2 3 4 5 6 7 8 9
          > 1 bearing
          > 2 bearing shoulder
          > 3 exhaust area
          > 4 CD hub stationary shoulder
          > 5 CD hub / disc pack (key slotted)
          > 6 threaded for dick back compression against a washer
          > 7 exhaust area
          > 8 bearing shoulder
          > 9 bearing
          >
          > Mike Passerotti
          >
          > -----Original Message-----
          > From: abnengineering@... [mailto:abnengineering@...]
          > Subject: RE: [TeslaTurbine] Shafted
          >
          >
          > How are you going to mount the cd's to the shaft?
          >
          > Mike Passerotti <mike.passerotti@...> wrote:
          >
          > >I want an aluminum shaft for my CD turbine. Anyone able to lend a hand?
          > >Its a small shaft, but I don't have access to a metal lathe. Any ideas
          on
          > >obtaining a small metal lathe?
          > >
          > >
          > >Mike Passerotti
          > >
        • McGalliard, Frederick B
          Mike. To really get the most from this simple but quite useable physics study, you may want to think a bit on instrumentation. You can use a small high speed
          Message 4 of 22 , Aug 22 11:32 AM
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            Mike. To really get the most from this simple but quite useable physics
            study, you may want to think a bit on instrumentation. You can use a small
            high speed DC motor to make this turbine a pump, if the nozzle construction
            is symmetric. And to apply a controlled torque when the turbine turns it as
            a generator. You will need information on the pressure at the nozzle exit
            inside the TT, and at the nozzle inlet. I wonder if a tire gauge would work?
            Some way to measure the air velocity would also be very handy. I have seen
            some designs for air flow sensors that use a temperature measuring device (a
            thermistor, thermocouple, or a diode) and a resistor. The resistor takes
            more heat to keep it at temperature when the wind is higher so with a bit of
            calibration out the window of the car, you can cover at least up to around
            100 mph (extrapolating, of course, since you would never drive over 70). The
            thermodynamics of this turbine are a bit hard to measure accuratly because
            the power level is so low but you can try and then you would have data you
            could use to really spiff up your final power turbine.

            -----Original Message-----
            From: Mike Passerotti [mailto:mike.passerotti@...]
            ...
            And yes, I'm building my first TT and playing with it. I'm not expecting a
            high performance TT but one I can make measurements on for design
            improvements without high cost of replacing parts. Plus, the clear case and
            clear discs will enable internal viewing of the flow.
          • Chuck
            I ve asked before, but what is the difference with what you are making and an air motor, like mechanics use to remove wheel nuts? ... From: Mike Passerotti
            Message 5 of 22 , Aug 22 12:34 PM
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              I've asked before, but what is the difference with what you are making and
              an air motor, like mechanics use to remove wheel nuts?
              ----- Original Message -----
              From: "Mike Passerotti" <mike.passerotti@...>
              To: <TeslaTurbine@yahoogroups.com>
              Sent: Thursday, August 22, 2002 9:25 AM
              Subject: RE: [TeslaTurbine] Shafted


              >
              > Keyslot on the shaft and keyslot on the cd hub, and a key. The shaft will
              > have one shoulder for the cd hub on one side. The cd washers will be cd
              > hubs cut down to just reaching the inside edge of the exhaust ports. The
              > other end of the shaft will have a threaded nut that will push on a washer
              > (slotted for the key also). The washer will compress the cd hubs against
              > the stationary shoulder. I'll setup the rotation and the threads so that
              > the nut won't come off while in operation. This is a low power
              application
              > so the key can be small square aluminum bar stock. If ballance is needed
              > I'll have to use a second key opposing the first key. Dang, that sentence
              > sounded too much like a patent description. I've written two mechanical
              > patents for an employer. What do you think about one versus two keys?
              >
              > I have access to a 50 W laser machine to cut my exhaust ports, rivet
              holes,
              > washers and key slots on the CDs.
              >
              > I'll be removing the gold layer on the CDs to prevent removal during
              > operation. When rubbing the gold layer off CDs with my fingers, I made a
              > mental note on just how easy it is to destroy CDs. Be careful with them.
              >
              > Here is an ascii profile of the shaft:
              >
              > _______
              > ___-| |-------------++---------____
              > 1 2 3 4 5 6 7 8 9
              > 1 bearing
              > 2 bearing shoulder
              > 3 exhaust area
              > 4 CD hub stationary shoulder
              > 5 CD hub / disc pack (key slotted)
              > 6 threaded for dick back compression against a washer
              > 7 exhaust area
              > 8 bearing shoulder
              > 9 bearing
              >
              > Mike Passerotti
              >
              > -----Original Message-----
              > From: abnengineering@... [mailto:abnengineering@...]
              > Sent: Thursday, August 22, 2002 1:49 AM
              > To: TeslaTurbine@yahoogroups.com
              > Subject: RE: [TeslaTurbine] Shafted
              >
              >
              > How are you going to mount the cd's to the shaft?
              >
              > Mike Passerotti <mike.passerotti@...> wrote:
              >
              > >I want an aluminum shaft for my CD turbine. Anyone able to lend a hand?
              > >Its a small shaft, but I don't have access to a metal lathe. Any ideas
              on
              > >obtaining a small metal lathe?
              > >
              > >
              > >Mike Passerotti
              > >
              > >
              > >
              > >
              > >
              > >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
              > <http://docs.yahoo.com/info/terms/>
              > >
              > >
              > >
              >
              >
              > Yahoo! Groups Sponsor
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              >
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              > <http://docs.yahoo.com/info/terms/> .
              >
              >
              > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
              >
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            • Mike Passerotti
              The air motors for impact wrenches are rotary vane. The TT is not a rotary vane engine or pump. The TT is closer to a torque converter on automatic
              Message 6 of 22 , Aug 22 1:44 PM
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                The air motors for impact wrenches are rotary vane. The TT is not a rotary
                vane engine or pump. The TT is closer to a torque converter on automatic
                transmissions where two plates in a fluid turn. In the torque converter, a
                plate is the input power which transmits the power through the fluid to the
                output plate. That was another of Tesla's ideas. The Tesla Turbine is
                where the fluid transfers power to output plates without an input plate to
                move the fluid. The fluid motion is provided by other methods such as
                pressure differential, thermal expansion, and more.

                Or are you asking what are the advantages to TT over rotary vane engine? I
                suppose I'll have to wait for TT tests and quantified efficiency, power to
                weight ration, torque specs and the like to answer that one. The rotary
                vane engine is pretty well documented in that respect.

                http://www.coopertools.com/brands/cleco/pdffiles/literature/sp164.pdf
                <http://www.coopertools.com/brands/cleco/pdffiles/literature/sp164.pdf>

                Mike Passerotti

                -----Original Message-----
                From: Chuck [mailto:chuckkessler@...]
                Subject: Re: [TeslaTurbine] Shafted


                I've asked before, but what is the difference with what you are making and
                an air motor, like mechanics use to remove wheel nuts?
              • star_wind_ca
                Mike, One place I buy all the weird mechanical parts you could every wish to find, yes they sell shating, small gear reducers, key less shaft couplers etc is
                Message 7 of 22 , Aug 22 7:44 PM
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                  Mike,

                  One place I buy all the weird mechanical parts you could every wish
                  to find, yes they sell shating, small gear reducers, key less shaft
                  couplers etc is SDP, their website is

                  http://www.sdp-si.com/

                  They have shim washers and a lot of parts though most are for
                  components that are 1/2" shaft size or smaller. They have a lot of
                  strange mechanical parts and certain you will find what you need.

                  They have what is called a shaft lock sleeve... it is two pieces
                  and as you tighten the nut the inner sleeve expands into the ID of
                  the part you want coupled to the shaft.... likely what ou are looking
                  for, simple but not exactly the lowest cost part... saves keyways and
                  precision IDS though.

                  Hope this helps

                  Dave


                  --- In TeslaTurbine@y..., Mike Passerotti <mike.passerotti@m...>
                  wrote:
                  > I want an aluminum shaft for my CD turbine. Anyone able to lend a
                  hand?
                  > Its a small shaft, but I don't have access to a metal lathe. Any
                  ideas on
                  > obtaining a small metal lathe?
                  >
                  >
                  > Mike Passerotti
                • Mike Passerotti
                  Thanks Dave. The key less shaft lock produces an extremely large radial clamping force which won t work for disc mounting. There isn t enough strength in
                  Message 8 of 22 , Aug 23 8:42 AM
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                    Thanks Dave.

                    The key less shaft lock produces "an extremely large radial clamping force"
                    which won't work for disc mounting. There isn't enough strength in thin
                    discs to handle the radial forces without twisting or distorting the discs.
                    I expect it would be good for solid gears that have a large hoop strength.

                    I think I'll end up with a stock shaft with a stock key slot and have the
                    discs cut out of clear plastic, then fiberglass sheet, then carbon fiber
                    sheet as I progress. I can use the key less shaft lock to create the
                    shoulders for the bearings. Thanks especially for pointing me to a source
                    I've never seen.


                    Mike Passerotti

                    -----Original Message-----
                    From: star_wind_ca [mailto:earthchanges@...]
                    Sent: Thursday, August 22, 2002 10:45 PM
                    To: TeslaTurbine@yahoogroups.com
                    Subject: [TeslaTurbine] Re: Shafted


                    Mike,

                    One place I buy all the weird mechanical parts you could every wish
                    to find, yes they sell shating, small gear reducers, key less shaft
                    couplers etc is SDP, their website is

                    http://www.sdp-si.com/ <http://www.sdp-si.com/>

                    They have shim washers and a lot of parts though most are for
                    components that are 1/2" shaft size or smaller. They have a lot of
                    strange mechanical parts and certain you will find what you need.

                    They have what is called a shaft lock sleeve... it is two pieces
                    and as you tighten the nut the inner sleeve expands into the ID of
                    the part you want coupled to the shaft.... likely what ou are looking
                    for, simple but not exactly the lowest cost part... saves keyways and
                    precision IDS though.

                    Hope this helps

                    Dave
                  • caaan1ca
                    ... hand? ... ideas on ... One place you can buy one is Sherline , the little Sherline lathe is a very capable hobbiest lathe, worth about $500 US, whole shop
                    Message 9 of 22 , Aug 24 5:28 PM
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                      --- In TeslaTurbine@y..., Mike Passerotti <mike.passerotti@m...>
                      wrote:
                      > I want an aluminum shaft for my CD turbine. Anyone able to lend a
                      hand?
                      > Its a small shaft, but I don't have access to a metal lathe. Any
                      ideas on
                      > obtaining a small metal lathe?
                      >
                      >
                      > Mike Passerotti


                      One place you can buy one is Sherline , the little Sherline lathe is a
                      very capable hobbiest lathe, worth about $500 US, whole shop including
                      milling machine and tooling is $1700 US. I don't have any affiliation
                      with Sherline just have used the equipment. The shaft should be made
                      of drill rod or similar hard steel, it must be strong. You can buy
                      these products (steel etc.) at industrial supply houses. I am new to
                      your list but plan to build a turbine shortly.

                      Arnold
                    • Ian Main
                      I once read somewhere that shafting should be made from 1045 steel.. I think it was the machinery s handbook. Actually, I ll check :) Hmm, well, says here
                      Message 10 of 22 , Aug 25 12:06 AM
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                        I once read somewhere that shafting should be made from 1045 steel..
                        I think it was the machinery's handbook. Actually, I'll check :)

                        Hmm, well, says here crankshafts are generally made from SAE
                        1046 and 1052. Axles are made from 1038 to 1045.

                        Ah, here we go.. shafts, heavy duty - 4340, 6150, 4615 4620. I
                        think the above 1046 to 1052 was mostly a discussion of carbon
                        range, ignoring alloys.

                        http://www.suppliersonline.com/propertypages/4340.asp
                        http://www.suppliersonline.com/propertypages/6150.asp

                        1045 is also listed for shafting on their site. 1045 is readily
                        available and fairly cheap.

                        Drill rod would have a lot higher carbon content and would be more
                        brittle.

                        On Sun, Aug 25, 2002 at 12:28:03AM -0000, caaan1ca wrote:
                        > --- In TeslaTurbine@y..., Mike Passerotti <mike.passerotti@m...>
                        > wrote:
                        > > I want an aluminum shaft for my CD turbine. Anyone able to lend a
                        > hand?
                        > > Its a small shaft, but I don't have access to a metal lathe. Any
                        > ideas on
                        > > obtaining a small metal lathe?
                        > >
                        > >
                        > > Mike Passerotti
                        >
                        >
                        > One place you can buy one is Sherline , the little Sherline lathe is a
                        > very capable hobbiest lathe, worth about $500 US, whole shop including
                        > milling machine and tooling is $1700 US. I don't have any affiliation
                        > with Sherline just have used the equipment. The shaft should be made
                        > of drill rod or similar hard steel, it must be strong. You can buy
                        > these products (steel etc.) at industrial supply houses. I am new to
                        > your list but plan to build a turbine shortly.
                        >
                        > Arnold
                        >
                        >
                        >
                        >
                        >
                        > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                        >
                      • Paul Anderson
                        ... Only in it s hardened state. In it s as-shipped hardness it is quite malleable. Drill rod is a good choice in this case as there is little shock, and
                        Message 11 of 22 , Aug 25 1:36 PM
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                          On Sun, 25 Aug 2002, Ian Main wrote:

                          >
                          > Drill rod would have a lot higher carbon content and would be more
                          > brittle.
                          >
                          Only in it's hardened state. In it's as-shipped hardness it is quite
                          malleable. Drill rod is a good choice in this case as there is little
                          shock, and drill rod is ground to dimension. For use in a tesla turbine,
                          it more than suitable and would only require having the ends cleaned up.
                          It would be an excellent fit with off-the-shelf bearings without any
                          further machining. It's also very readily available.


                          ---
                          Paul Anderson
                          geeky1!paul
                          "Nature has been kinder to us than we had any right to expect.
                          --- Freeman Dyson
                        • Mike Passerotti
                          Thank you all very much for helpful advice. I think I ll start with off the shelf parts. I ll just buy a shaft and use collars and bearings to match. I ll
                          Message 12 of 22 , Aug 26 10:57 AM
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                            Thank you all very much for helpful advice. I think I'll start with off the
                            shelf parts. I'll just buy a shaft and use collars and bearings to match.
                            I'll have to laser cut my discs and spacers/washers. I think this is about
                            as cheap as I can get.

                            I really like the poor man's lathe. I'll start scavenging for a motor,
                            pulleys and bearings.

                            Wouldn't it be nice to have a coop near home where we could share tools?


                            Mike Passerotti
                          • the_maniacal_engineer
                            There are two concerns with shafting, one is strength, one is stiffness, or more properly, stiffness to weight. The first sets the limit on torque, the second
                            Message 13 of 22 , Sep 5, 2002
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                              There are two concerns with shafting, one is strength, one is
                              stiffness, or more properly, stiffness to weight. The first sets the
                              limit on torque, the second sets the limit on RPM.

                              Aluminum has about the same stiffness to weight ratio as steel, but
                              if you use aluminum the discpack gets larger as a proportion of the
                              total rotating mass and so the critical frequency goes down. Using
                              hollow shafting reduces the mass and the critical frequency goes up.

                              The carbon content or alloying of shafting will only affect the
                              strength and the torque it can carry - speed is unaffected.

                              Chris

                              --- In TeslaTurbine@y..., Ian Main <ian3@s...> wrote:
                              > I once read somewhere that shafting should be made from 1045 steel..
                              > I think it was the machinery's handbook. Actually, I'll check :)
                              >
                              > Hmm, well, says here crankshafts are generally made from SAE
                              > 1046 and 1052. Axles are made from 1038 to 1045.
                              >
                              > Ah, here we go.. shafts, heavy duty - 4340, 6150, 4615 4620. I
                              > think the above 1046 to 1052 was mostly a discussion of carbon
                              > range, ignoring alloys.
                              >
                              > http://www.suppliersonline.com/propertypages/4340.asp
                              > http://www.suppliersonline.com/propertypages/6150.asp
                              >
                              > 1045 is also listed for shafting on their site. 1045 is readily
                              > available and fairly cheap.
                              >
                              > Drill rod would have a lot higher carbon content and would be more
                              > brittle.
                              >
                              > On Sun, Aug 25, 2002 at 12:28:03AM -0000, caaan1ca wrote:
                              > > --- In TeslaTurbine@y..., Mike Passerotti <mike.passerotti@m...>
                              > > wrote:
                              > > > I want an aluminum shaft for my CD turbine. Anyone able to lend
                              a
                              > > hand?
                              > > > Its a small shaft, but I don't have access to a metal lathe.
                              Any
                              > > ideas on
                              > > > obtaining a small metal lathe?
                              > > >
                              > > >
                              > > > Mike Passerotti
                              > >
                              > >
                              > > One place you can buy one is Sherline , the little Sherline lathe
                              is a
                              > > very capable hobbiest lathe, worth about $500 US, whole shop
                              including
                              > > milling machine and tooling is $1700 US. I don't have any
                              affiliation
                              > > with Sherline just have used the equipment. The shaft should be
                              made
                              > > of drill rod or similar hard steel, it must be strong. You can buy
                              > > these products (steel etc.) at industrial supply houses. I am new
                              to
                              > > your list but plan to build a turbine shortly.
                              > >
                              > > Arnold
                              > >
                              > >
                              > >
                              > >
                              > >
                              > > Your use of Yahoo! Groups is subject to
                              http://docs.yahoo.com/info/terms/
                              > >
                            • bladefalcon2002
                              With regards to hollow shafting, do you think that this could be used as the exhaust port ? - it would increase the circular laminar flow quite a bit (and as a
                              Message 14 of 22 , Sep 5, 2002
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                                With regards to hollow shafting, do you think that this could be
                                used as the exhaust port ? - it would increase the circular laminar
                                flow quite a bit (and as a result probably increase efficiency even
                                more) via the increased path.An exhaust hole/holes equivilant to the
                                predicted max. flow could be placed around the circumference of the
                                shaft between the discs directly into the hollow shafting. Further,
                                if the "exhaust holes" to the hollow shafting were carefully placed
                                at differing centres at each spacing between discs, I could see a
                                vortex flow being created in the very centre of the turbine. I have
                                no idea what type of effect this might create but I could imagine
                                some pretty wild enhanced flows being created at high RPMs. All this
                                would have to be in steel of course. I can also imagine that the
                                possibility of running ancillary areas such as compression to inlet,
                                and placing turbines in tandem, pumps to a steam condensor system,
                                etc would possibly be aided in such an exhaust design.





                                @y..., "the_maniacal_engineer" <chris@p...> wrote:
                                > There are two concerns with shafting, one is strength, one is
                                > stiffness, or more properly, stiffness to weight. The first sets
                                the
                                > limit on torque, the second sets the limit on RPM.
                                >
                                > Aluminum has about the same stiffness to weight ratio as steel,
                                but
                                > if you use aluminum the discpack gets larger as a proportion of
                                the
                                > total rotating mass and so the critical frequency goes down. Using
                                > hollow shafting reduces the mass and the critical frequency goes
                                up.
                                >
                                > The carbon content or alloying of shafting will only affect the
                                > strength and the torque it can carry - speed is unaffected.
                                >
                                > Chris
                                >
                                > --- In TeslaTurbine@y..., Ian Main <ian3@s...> wrote:
                                > > I once read somewhere that shafting should be made from 1045
                                steel..
                                > > I think it was the machinery's handbook. Actually, I'll check :)
                                > >
                                > > Hmm, well, says here crankshafts are generally made from SAE
                                > > 1046 and 1052. Axles are made from 1038 to 1045.
                                > >
                                > > Ah, here we go.. shafts, heavy duty - 4340, 6150, 4615 4620. I
                                > > think the above 1046 to 1052 was mostly a discussion of carbon
                                > > range, ignoring alloys.
                                > >
                                > > http://www.suppliersonline.com/propertypages/4340.asp
                                > > http://www.suppliersonline.com/propertypages/6150.asp
                                > >
                                > > 1045 is also listed for shafting on their site. 1045 is readily
                                > > available and fairly cheap.
                                > >
                                > > Drill rod would have a lot higher carbon content and would be
                                more
                                > > brittle.
                                > >
                                > > On Sun, Aug 25, 2002 at 12:28:03AM -0000, caaan1ca wrote:
                                > > > --- In TeslaTurbine@y..., Mike Passerotti
                                <mike.passerotti@m...>
                                > > > wrote:
                                > > > > I want an aluminum shaft for my CD turbine. Anyone able to
                                lend
                                > a
                                > > > hand?
                                > > > > Its a small shaft, but I don't have access to a metal
                                lathe.
                                > Any
                                > > > ideas on
                                > > > > obtaining a small metal lathe?
                                > > > >
                                > > > >
                                > > > > Mike Passerotti
                                > > >
                                > > >
                                > > > One place you can buy one is Sherline , the little Sherline
                                lathe
                                > is a
                                > > > very capable hobbiest lathe, worth about $500 US, whole shop
                                > including
                                > > > milling machine and tooling is $1700 US. I don't have any
                                > affiliation
                                > > > with Sherline just have used the equipment. The shaft should
                                be
                                > made
                                > > > of drill rod or similar hard steel, it must be strong. You can
                                buy
                                > > > these products (steel etc.) at industrial supply houses. I am
                                new
                                > to
                                > > > your list but plan to build a turbine shortly.
                                > > >
                                > > > Arnold
                                > > >
                                > > >
                                > > >
                                > > >
                                > > >
                                > > > Your use of Yahoo! Groups is subject to
                                > http://docs.yahoo.com/info/terms/
                                > > >
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