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Neat method to cut gears.

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  • Neat method to cut gears.

    What do you guys think. Damn I cant paste it .Its Andys machines . He uses a slitting saw.

  • #2
    https://www.youtube.com/watch?v=eC-OctJoWv4
    Nev.

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    • #3
      Thats it Thanks.

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      • #4
        For large modulus (or small DP) gears, it seems like a reasonable way to get a faceted tooth.
        The number of cuts, of course, will determine how closely it approximates an involute.
        It probably needs a fair amount of polishing and/or running in to smooth the facets and saw marks.
        SE MI, USA

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        • #5
          I wonder what size gear and tooth count will limit its ability to cut with a 2 mm slitting saw?

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          • #6
            I think that guy, Andy, deserves some serious kudos for the presentation. He's well spoken; no "ums" or "go ahead ands" and with all that overlay work, wow, that was a serious quantity of video production effort.
            in Toronto Ontario - where are you?

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            • #7
              The thickness of the saw blade has to be less than the space between the teeth.
              The diameter of the pitch circle is the module time the number of teeth = m*N,
              its circumference is pi*m*N,
              so the width of the space between the teeth is the circumference divided by 2N (the width of the tooth and the space between the teeth are equal here), or t = pi*m/2.
              Note that this does not depend on the number of teeth.

              The thickness of the saw blade needs to be a bit smaller than this to fit between the teeth. For a 2 mm thick blade, the minimum modulus would be 1.27 mm. In practice this module would need to be a larger, say 2 mm.
              SE MI, USA

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              • #8
                Excellent presentation. He saved $60 for a gear cutter, but probably spent all day making a gear with the slitting saw. Obviously a very good machinist with good math skills. Personally, I would have bought the gear cutter.
                Brian Rupnow
                Design engineer
                Barrie, Ontario, Canada

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                • #9
                  Interesting. Once you get the process down pat you could probably move along pretty fast.

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

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                  • #10
                    I think that guy, Andy, deserves some serious kudos for the presentation.
                    Ditto! Far too many you-tubers don't write themselves a script before hand, much less rehearse first or edit afterwards - they just wing it. Planning what is going to be said, and shown, and omitting any time wasting repetitive filler makes all the difference.
                    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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                    • #11
                      Yep, that was a high quality video in all respects. And I sure did like the voicing. No extra nonsense. I bet it took longer to do the editing with special effects than it did to cut the gear itself. And that's saying something what with all the setup and 120 passes!

                      Brian, for the smaller sizes I'd agree. But this looks like a seriously big gear which would require a seriously big gear cutter. And as he said in the opening his mill doesn't have the conojes to turn that big a cutter. A quick check on our Canadian Ebay tells me that a mod4 gear cutter is 3.5" diameter. And the cheapest NOS offering is $120.

                      Looking at the 2mm slitting saw and the amount of metal removed I'm also thinking that even if he could slow it down enough that it's still the equivalent of removing a 3/8 square body of metal in one go. I suppose the gear cutter could be fed in with smaller steps. But it would still be one heck of a chip load for the final passes on as light a machine as he was using.
                      Chilliwack BC, Canada

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                      • #12
                        Originally posted by brian Rupnow View Post
                        Excellent presentation. He saved $60 for a gear cutter, but probably spent all day making a gear with the slitting saw. Obviously a very good machinist with good math skills. Personally, I would have bought the gear cutter.
                        In my world, it is not just the 60$, but the minimum 28 days for delivery. I live in rural Alberta with no supply house likely to stock a cutter even within the province, much less the local to me places.

                        I can ( and have) hand ground a 4$ single point tool bit and made a holder to generate a pinion gear in a day from 1" MS plate. Setting up and using a commercial cutter takes some time too - likely a couple hours.

                        The charm in Andy's method is the huge reduction in chip load from a profile cutter to a slitting saw.
                        Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

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                        • #13
                          I've cut gears on my 4th axis CNC mill in a similar fashion except it cuts the exact gear tooth profile. My CAD software has the tooth profiles. First rough out most of the material between teeth. Take a tooth face pass feeding in the Y axis as the 4th axis rotates slightly, back out, move about .025" in X and repeat until the width of the gear is done. Index blank and repeat until all of one side of each tooth is done. Then do the other side of each tooth.

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