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Is it possible to machine a Oval Shaft

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  • #31
    I do not see any oval and I don't even see a lathe.

    Did you mix up your photos?



    Originally posted by oxford View Post
    Here was my one and only attempt at turning an oval on the lathe. It was done with the offset center method.
    Paul A.
    SE Texas

    And if you look REAL close at an analog signal,
    You will find that it has discrete steps.

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    • #32
      You guy’s have supplied a lot of info&ideas ,I have all summer to decide what I will do as I’m done riding the high country till Dec.Nice job on machining oxford,a couple more pics for clarity.

      The space between Arrows is what I was wanting to reinforce internally and other pic shows Oval shape.My guess would be these tubes are extruded some how as the tolerance is close.

      Thanks again! Click image for larger version

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      • #33
        simply do a carbon/epoxy reinforcement (blow up a piece of bicycle tube inside).

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        • #34
          Are you wanting to make it out of solid material? Aluminum I would guess. Between the arrows there is a reduction in the cross section. Is the bigger side round or also oval shaped? Is it your plan to slide the reinforcement piece down the bigger long end? Me, I would just go over to the belt grinder and freehand the shape. I would make two different "plugs" out of wood to the exact size you need. Then I would screw one plug to one end of my material and the other plug to the other end of the material and then use the plugs for reference while grinding on the belt grinder. With patience and due diligence I could get it to fit nearly perfectly. But I have a lot of experience on a belt grinder. I mean lots and lots.
          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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          • #35
            If you're just reinforcing that section do it with fiber and resin by blocking the tube and pouring it in. It's fast, easy and effective. The weight savings from trying to keep it hollow is not worth the effort, its a couple of ounces and you're not backpacking it! Did you have one fail at that spot?
            Location: Jersey City NJ USA

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            • #36
              Originally posted by gellfex View Post
              If you're just reinforcing that section do it with fiber and resin by blocking the tube and pouring it in. It's fast, easy and effective. The weight savings from trying to keep it hollow is not worth the effort, its a couple of ounces and you're not backpacking it! Did you have one fail at that spot?
              The resin & fibre route may be the best as others have mentioned as well.Been using this setup for 8 yrs with no issues but have read that some fail digging in concrete snow.Some Instructors test these shovels by extending handle full length laying them face down on frozen ground then stand on it with one foot wearing ski boots and stomp with other foot to make them fail.I don’t really agree with that as most fail,I’m sure most live recovers are not concrete hard snow.

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              • #37
                I've not taken an avalanche class, but aren't they powder? 'concrete snow' doesn't seem like stuff that will avalanche very well!
                Location: Jersey City NJ USA

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                • #38
                  Ok guys, since this a free thinking exercise, how about this. Mount your stock in a 4 jaw, offset the stock by an appropriate amount. Mount a 4 jaw revolving tailstock chuck, offset work a like amount and direction as in the headstock chuck. Turn until you get the profile you want on one side then rotate the work 180 degrees, turn until you get a matching profile on the other side.

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                  • #39
                    Was contemplating the reinforcing issue while puttering. Seems to me all you need is compression blocking inside to keep the tube from collapse failure. The tube will not fail from extension ie tensile strength failure. It would fail from the narrow diameter ends of the ellipse bulging at the strain focal point and one side of the major diameter folding or collapsing inward. All you need is cast blocking to prevent that, no glass or such needed.
                    Location: Jersey City NJ USA

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                    • #40
                      Originally posted by tmc_31 View Post
                      Ok guys, since this a free thinking exercise, how about this. Mount your stock in a 4 jaw, offset the stock by an appropriate amount. Mount a 4 jaw revolving tailstock chuck, offset work a like amount and direction as in the headstock chuck. Turn until you get the profile you want on one side then rotate the work 180 degrees, turn until you get a matching profile on the other side.
                      Wouldn’t this be the same as turning between offset centers?

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                      • #41
                        I could do it for you on my rose engine as long as it's only 6" long

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                        • #42
                          Originally posted by gellfex View Post
                          I've not taken an avalanche class, but aren't they powder? 'concrete snow' doesn't seem like stuff that will avalanche very well!
                          When I say concrete snow I’m referring to the deposit of snow after a Avalanche has taken place.There is numerous types,I’ve seen hard blocks the size of Volkswagen’s the are very hard and other’s that are Loose Snow which can be Shovelled.All Avalanches firm up after the snow stops moving,some quicker than others.
                          Originally posted by gellfex View Post
                          Was contemplating the reinforcing issue while puttering. Seems to me all you need is compression blocking inside to keep the tube from collapse failure. The tube will not fail from extension ie tensile strength failure. It would fail from the narrow diameter ends of the ellipse bulging at the strain focal point and one side of the major diameter folding or collapsing inward. All you need is cast blocking to prevent that, no glass or such needed.
                          I assume your talking about a adding a flat brace on the longest portion of the Oval,my thought was to cut a Aluminium Flat bar 6-7” long stepped down for smaller portion and slide down from large end.

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                          • #43
                            Originally posted by Tundra Twin Track View Post
                            I assume your talking about a adding a flat brace on the longest portion of the Oval,my thought was to cut a Aluminium Flat bar 6-7” long stepped down for smaller portion and slide down from large end.
                            No, I'm still talking about pouring resin into the section you're concerned about. I'm just saying it needs no tensile strength from fiber at all, I think the issue is all resisting collapse, or compression. The long axis is not the one that will collapse!


                            Location: Jersey City NJ USA

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                            • #44
                              If I was going to produce the profile, I would push it through profiled rollers which can be adjusted for their spacing. The original profile would have been easy to make, if it looked ok, then it was. To copy an existing profile, some experimentation would be necessary to get a match. Any swaging would be easer to do while the tube was still round section. The swaged end would need to be profiled in a separate operation.

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                              • #45
                                Originally posted by Paul Alciatore View Post
                                I do not see any oval and I don't even see a lathe.

                                Did you mix up your photos?




                                Paul, I see the correct pics and yes there is no lathe present.

                                Its hard to photograph, you can barely tell from the side views of what going on.

                                The one view of the top you can see it and look below the square stock that is welded on and you can see the “oval” profile of the big end.

                                I made this quite a few years ago and didn’t take any pictures of doing it. It is a bracelet mandrel for jewelry making. I made it for the wife for Christmas one year.

                                It was made out of 304 stainless, it took forever, sucked doing it with the interrupted cuts, and my lathe was not happy about doing it.

                                I’d have to measure to be sure but it’s around 12” long on the oval part and probably started with 3” OD stock.

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