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where to buy air bearing spindle for T&C

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  • #16
    Originally posted by oldtiffie
    Dennis.

    No use at Uluru mate. They use all the "O" rings as intra-uterine contraceptive devices.
    http://en.wikipedia.org/wiki/Vaginal_ring

    The air that escapes from between the work-head and the quill is pretty effective - but the "grindings" don't seem to do much harm.
    You're on the right track but I was thinking more of friction devices to gently arrest the movement of the shaft rather than assisting it.

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    • #17
      That'd do it

      Yep.

      That'd do it Dennis.

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      • #18
        A friend built an air-spindle and got it working without fancy tooling. Can't find his vid on YouTube.

        Anyhow, there are a few tricks to success:
        The spindle has to be perfectly round and cylindrical. Grinding is not enough, because it often enough isn't really round. Do the final finish by lapping.

        The bushing where the spindel runs in was made out of brass. You don't have contact, so it isn't a bearing surface. The air needs to build a cushion, so you have to mill small pockets/reservoirs into the bushing. I think he made them 2*2 mm or such. The air going into those pockets needs to be throtteled. He made 0.3mm holes.

        He doesn't use any oil, only filtered air. Out of fun, he reved it up to 40000 RPM and let it spin free. It took several hours to stop. The spindle lifted at 1.5 bar and fully floated and lifted a drill chuck with 2 bar (or was it 3?).

        Instraed of brass -that isn't perfect at all- you could use ABCoating made by Diamant (Moglice). Then you'd need a mandrel to cast the bearing surface. The spindle itself is a tad smaller. Either use the mandrel and lap it down to make our spindle, or make a new one. IIRC, the spindle was 0.01mm smaller in diameter than the bore.

        I have no personal experience.


        HTH,
        Nick

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        • #19
          Originally posted by dp
          I wonder how much it would cost to make a set of those castings...
          Castings wouldn't help you much. The hurdle on making an air bearing is lapping the bore straight and round. Phil Duclos' build basically says to bore a random hole in a block of steel, lap it until it's round and straight, and then turn shaft to fit it.

          IIRC, you need about 3 tenths clearance for optimal float, and that clearance needs to be uniform across the entire length.

          Nick, presuming that there aren't two German model engineers who have successfully built air bearing spindles , that video and build log is posted on the Yahoo Quorn group. Very impressive.
          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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          • #20
            and that clearance needs to be uniform across the entire length.
            What he made is, that he had at both ends a bushing just at about 25% length. Inbetween, there was a recess (bigger bore) that allowed air that already passed to leak out.


            Nick

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            • #21
              Originally posted by MuellerNick
              What he made is, that he had at both ends a bushing just at about 25% length. Inbetween, there was a recess (bigger bore) that allowed air that already passed to leak out.
              Right, I've seen some designs that have an air "bushing" (for lack of a better description) that stabilizes the ends. So the spindle chamber is dumb bell shaped.

              But my KO Lee air spindle is perfectly straight, and barely leaks at all. Perhaps it's a tolerance issue?

              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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              • #22
                and barely leaks at all. Perhaps it's a tolerance issue?
                Certainly. That's why I suggested the ABCoating (AB stands for Air Bearing). You can cast that to almost about 1┬Ám. The minute gap comes from the wax (release agent). If thats too tight, you can lap the spindle down until satisfied.

                Again, I didn't do it (yet).


                Nick

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                • #23
                  Girls, I don't want to build one...I want to buy something!

                  I want to buy something even if it is not a air bearing spindle. I want to sharpen my end mills.
                  Location: The Black Forest in Germany

                  How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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                  • #24
                    Darex makes, or made, a prett cheap air bearing spindle that holds 5C's. It was intended to be mounted to a surface grinder to sharpen end mills that way.

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                    • #25
                      Originally posted by Black Forest
                      I want to buy something even if it is not a air bearing spindle.
                      Ebay. They're dirt cheap -- I think I paid $150 for my KO Lee, and it's immaculate. Strongly suggest you get a 5C air bearing spindle -- some have proprietary collets that are very hard to find.

                      I bought my air bearing from a pro grind shop in Rhode Island, and I happened to be on a business trip nearby, so I just picked it up. Sadly, I flew back to Austin the day after the Liquid Bomber incident, so air travel was Red Flagged, and the TSA guys went nuts that I wanted to bring a 50 lb air bearing on the plane.

                      This was the result (notice the TSA seals)

                      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                      • #26
                        Work-head

                        Originally posted by Black Forest
                        I want to buy something even if it is not a air bearing spindle. I want to sharpen my end mills.
                        Thanks BF.

                        You've now defined your needs as opposed to your wants.

                        This head:








                        http://i200.photobucket.com/albums/a..._grinder22.jpg

                        on this machine:
                        http://i200.photobucket.com/albums/a...l_grinder3.jpg

                        http://i200.photobucket.com/albums/a...l_grinder5.jpg

                        http://i200.photobucket.com/albums/a..._grinder23.jpg

                        at:
                        https://www.machineryhouse.com.au/Pr...stockCode=G198

                        cost @AU$4,250 x 0.88 ~ US$3,750

                        will do the job very well although the work-head alone on a surface grinder will do just as well.

                        Air quills are very nice to have but are not really necessary as the work-head as shown will do the job.

                        And so will the "Spindexer"!!!

                        I suggest that you shop around on the 'net or eBay etc.

                        Comment


                        • #27
                          The Duclos air spindle is not that hard to make. It's made from a cheap import spindex. The spindle dia. is not super critical and can vary a thou or two. If your lathe can hold a uniform dia. over a 8 or 10" length, that's all you need. The surface finish is not too critical either since it doesn't touch anyrthing.

                          Drilling and machining the air passages and in the spindex casting is more work than making the spindle.

                          RWO

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                          • #28
                            Originally posted by RWO
                            The Duclos air spindle is not that hard to make. It's made from a cheap import spindex.
                            You're thinking of a different project. Phil Duclos' air bearing is not made from a spindex, and he describes that it's absolutely critical to maintain straightness within 2 or 3 tenths across the length of the bearing, or it won't float, or will require an immense amount of air to float.

                            Phil describes boring the bore, then lapping for straightness. No coincidentally, the other popular air bearing design (in the "Greatly Improved Quorn" articles) does the same process: bore the hole, and lap to tolerance with a cast iron lap.
                            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                            Comment


                            • #29
                              Originally posted by lazlo
                              You're thinking of a different project. Phil Duclos' air bearing is not made from a spindex, and he describes that it's absolutely critical to maintain straightness within 2 or 3 tenths across the length of the bearing, or it won't float, or will require an immense amount of air to float.

                              Phil describes boring the bore, then lapping for straightness. No coincidentally, the other popular air bearing design (in the "Greatly Improved Quorn" articles) does the same process: bore the hole, and lap to tolerance with a cast iron lap.
                              Robert,

                              I haven't seen the Duclos article but have the HSM Improved Quorn series. Does Duclos port air into the center plenum like the Quorn article? I can't quite tell on your KO Lee picture but is it doing the same thing?
                              .
                              "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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                              • #30
                                Walter Mueller's (Much Improved Quorn) had a pair of inlets a third of the way in from each end, with a slight groove. I *think* Glenn Wilson/Phil Duclos' air bearing was the same configuration -- I'll check when I get home (it's in one of the Metalworking hard covers).

                                By the way, this is Lane's:

                                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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