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Air Bearing Question..... Spindle & Housing Tolerances...... Anyone....

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  • Air Bearing Question..... Spindle & Housing Tolerances...... Anyone....

    I have a really nice KO Lee air bearing, however the spindle tends to stick a bit. It's not just in one spot, it can just happen suddenly about any where throughout the spindle's travel. I removed the spindle, wiped it clean and made sure that it was free of any oil, nicks, etc., same with the housing and it made no difference. It actually moves with less resistance with out any air being applied to it.
    I've varied the air pressure from 30 psi to over the recommended 80 psi. and it made no difference, actually the lower the preassure the better it feels, but it still sticks. Here is the reason.......I think......... There is a lot of air leakage comming out of the right hand side of the housing where the spindle exits the bore. The leak seams to be concentrated between the 11 and 2 o-clock position. What I think is happening is the uneaven exit of air around the spindle is forceing it against the opposite side of the bore causing it to stick. Thats why it moves with less resistance with no air. I don't know what the tolerances are on these, my guess is a couple tenths. I think I may have a simple fix but I'm not 100% sure if it'll work. My idea is to make a flange to bolt to the housing with a tight tolerance ground ID. The flange doesn't have to be any more than 1/4" in thickness. My thought is this flange will act as seal, altough it won't touch the spindle it will just even up the gap around the spindle and hopefully allow for even air flow around it eliminating any binding.
    If any one doesn't quite get what my idea is just let me know and I'll post some pictures.

    JL.....................

  • #2
    If the "stick a bit" does not really impede the function of the air quill and if it can be used as required without too much effort or problem, I'd suggest it be left "as is" as attempts to solve a small problem may may it a bigger one and perhaps beyond use or recovery.

    Perhaps it will "wear in" over time - and perhaps not too.

    Comment


    • #3
      It's well worn in altough it doesn't look it. It does impede the function at leat it does to me as that effortless glide of the spindle just isn't there and with out it you don't have the sense of feel.

      JL................

      Comment


      • #4
        I don't know what the end of that air spindle looks like, but this idea may be a useful test. I would put a clamp across the outside of the spindle in such a way that the applied force tends to close the gap that you suspect and open gaps in the perpendicular direction. If you apply a clamping pressure large enough to produce a small deformation (not plastic deformation) you should see some change in behavior. It is a simple test, you just have to be careful not to produce damage. A better test involves a ball bearing of just the right size - something you probably don't have. A fix involves a ball bearing of the correct size, some lube and a press.

        Comment


        • #5
          Originally posted by JoeLee View Post
          It's well worn in altough it doesn't look it. It does impede the function at leat it does to me as that effortless glide of the spindle just isn't there and with out it you don't have the sense of feel.

          JL................
          As the main use of the air quil is probably sharpening the spiral flutes (end edges as well) the "feel" theat I am after with my quills (air and other) is that I can feel the "finger" on the flutes of the cutter.

          http://i200.photobucket.com/albums/a...ER32-C5-33.jpg

          http://i200.photobucket.com/albums/a...ER32-C5-35.jpg

          http://i200.photobucket.com/albums/a...ER32-C5-36.jpg

          http://i200.photobucket.com/albums/a...ER32-C5-43.jpg

          http://i200.photobucket.com/albums/a...ER32-C5-42.jpg

          http://i200.photobucket.com/albums/a...ER32-C5-31.jpg

          http://i200.photobucket.com/albums/a..._grinder18.jpg

          http://i200.photobucket.com/albums/a..._grinder20.jpg

          http://i200.photobucket.com/albums/a..._grinder21.jpg

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

          http://i200.photobucket.com/albums/a..._grinder17.jpg

          http://i200.photobucket.com/albums/a...-grinder27.jpg

          This stuff on other than air quills ir set up to show the principle involved (ie "mocked up") and while on tool and cutter grinders can mostly be done on a surface grinder with a "saucer" wheel anda bit of lateral thinking and ingenuity - and it is just as functionally accurare as the air quill..

          My air quill is fine but if it is set level with air supplied it will "creep" and increase longitudinal speed until it hits a stop or a job or a wheel unles it is "nipper"/clamped whennot in use - a slope of less that 1/8" per foot (1 in 96 ~ 0.60 degrees) but because of "stiction" and some "moving" friction I have no "sliding" problem there with the "other" (non-air) quills.

          Here is my air quill:

          http://i200.photobucket.com/albums/a...Air-quill2.jpg

          http://i200.photobucket.com/albums/a...Air-quill1.jpg

          http://i200.photobucket.com/albums/a...Air-quill4.jpg

          http://i200.photobucket.com/albums/a...Air-quill6.jpg

          http://i200.photobucket.com/albums/a...Air-quill5.jpg

          http://i200.photobucket.com/albums/a...Air-quill7.jpg

          Comment


          • #6
            Maybe one of the pads has more oil in it or gunk than the other. Try rotating the pads and check for chirality - if yes, then replace the pad(s)

            Comment


            • #7
              Originally posted by oldtiffie View Post
              If the "stick a bit" does not really impede the function of the air quill and if it can be used as required without too much effort or problem, I'd suggest it be left "as is" as attempts to solve a small problem may may it a bigger one and perhaps beyond use or recovery.

              Perhaps it will "wear in" over time - and perhaps not too.
              The idea of the air spindle is totally lost if it drags.

              And 'fixing' something by wearing it in is not the way things are fixed. Crap doesn't turn to gold no matter how much it 'wears in'.
              Amount of experience is in direct proportion to the value of broken equipment.

              Comment


              • #8
                Perhaps so - perhaps not.

                If the OP wants to stick to "perfect" and not use the air quill until it is "perfect" then he may not get around to using it at all.

                If it is less than ideal but is still quite functional - then if it were me I'd use it.

                Its the OP's call after all as it is his air quill.

                Comment


                • #9
                  Originally posted by oldtiffie View Post
                  then he may not get around to using it at all.
                  Pot, kettle, black.

                  Is there any chance you could possibly stuff any more **** into this stooge Pic?

                  http://s200.beta.photobucket.com/use...der23.jpg.html

                  Comment


                  • #10
                    air bearing

                    Originally posted by Machtool View Post
                    Pot, kettle, black.

                    Is there any chance you could possibly stuff any more **** into this stooge Pic?

                    http://s200.beta.photobucket.com/use...der23.jpg.html
                    clean it with car wax. and wipe it with a soft clouth.

                    Comment


                    • #11
                      Have you been feeding it "clean" air? Well filtered, no oil, dry air? Did you make the mistake of connecting it using an air hose that had been used for general shop use and was contaminated by dirt, oil, etc.? Did this start happening recently or was this behavior noticed immediately after buying it (used?)?

                      Comment


                      • #12
                        The air is usally supplied to the anulus via very small orifices. If you have an orifice blocked at the 6 Oclock position you will get the effect you describe. Look for a means of access to the orifice (one feeding each recess pad) or come up with a way to backflow through the offending orifice with compressed air.

                        Phil

                        As the previous poster pointed out, very clean air is a must.
                        Last edited by philbur; 03-01-2013, 09:10 AM.

                        Comment


                        • #13
                          Originally posted by oldtiffie View Post
                          Perhaps so - perhaps not.

                          If the OP wants to stick to "perfect" and not use the air quill until it is "perfect" then he may not get around to using it at all.

                          If it is less than ideal but is still quite functional - then if it were me I'd use it.

                          Its the OP's call after all as it is his air quill.
                          If he wants to use an air spindle, then a sticking spindle is not one to use but to repair. Using a broken tool will end up in more broken tools.

                          If you would use even half the stuff you pose you would know this kind of elementary thing.
                          Amount of experience is in direct proportion to the value of broken equipment.

                          Comment


                          • #14
                            Tiffie, I don't have a spin jig, I've used them before but they don't have the same no drag feel that an air spindle should have. If you can develop the feel for useing one when sharpening your end mills that geat but with the drag thats on this spindle I have it makes it very difficult to maintain the delicate sense of feel that you need to keep the end mill in contact with the finger.
                            As far as the replies about cleaning and air supply etc. Those were the first things I looked for. In it's first life it was used in a tool sharpening shop, it was used for it's intended purpose but cared for and not abused.
                            The first picture shows the bore, this one has 3 air holes evenly spaced out around the center of the bore, every thing is clean.
                            the second picture where I indicate with the red marks is where the heavy air loss is comming from. It must be that there is some wear in the bore that is the cause. My thought is to make a flange like the one shown in the last picture, wit a close fit ID to seal the gap and hopefully evenly distribute the air around the spindle, it;s an easy and simple fix, but I just don't know if it'll work.
                            The idea that was mentioned about clamping a half or quarter round piece of plastic around the leak area would be a good way to test my idea. If it works then I can procede to the permanent fix.

                            JL.....................


                            Comment


                            • #15
                              Note: I've tried reversing the spindle and the leak is still at the same location that is marked so with out a doubt it's in the bore and not the spindle.

                              JL...............

                              Comment

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