That is the 2nd version posted on 12/14/2021. The first version I posted on 12/3/2021. The 1st one had outer gears with the same outside and approximate inside diameters, and wonky module numbers, to try to use the same size pinions for both.
In the 2nd version that you are doing, I had tried to make the pinion pairs one piece, by fusing a tube between the two of them. (I'm not sure that it took.) Did you add any provision for a bearing between the pinions and the spider carrier? It would seem like that would be necessary for a good working model. The module tooth shape was auto generated by Freecad using the Involute Gear option in the Part Design work bench. I did not "draw" them, just typed in a module number, and a number of teeth, Freecad did the rest. It makes it stupid easy. https://wiki.freecadweb.org/PartDesign_InvoluteGear What's even better just clicking on the involute gear you created, lets you change any of the parameters to either change the drawing you made or create a new gear. With a few mouse clicks I was able to redo the whole assembly to make one with 125t/126t ring gears and 50t/51t pinions and a 1.0module that would be the same overall sizes and should have reduction of 84:1. I guess there is also a more complex and capable separate Gear workbench for Freecad, but I have not installed or played with it. https://wiki.freecadweb.org/FCGear_Workbench There are a few Freecad tutorial videos that step through using these tools. And they really make creating the gears and even the harder things like laying out your gear center spacing child's play. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: John Dammeyer <jo...@autoartisans.com> Sent: Wednesday, December 15, 2021 2:00 PM To: 'Enhanced Machine Controller (EMC)' <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] Harmonic Drive [EXTERNAL EMAIL] Be sure links are safe. Yikes. Versions? I thought there was only one version. Outer gears are the same OD, have different ID. Pinion gears are different diameters due to extra tooth. cid:image001.png@01D7F19F.CBD7A380 I've printed one set of 2 pinions. And one outer gear (BLUE -- Cut1 with 1.25 and 100T). Still to print is the other Gear (GREEN, -- Cut001 with 1.25 and 101T) and 2 more pinion sets. I've created an input shaft. I'm guessing we hold the 100T gear fixed and the 101T is the one turning at the 67:1 ratio when turning the input shaft (pinion cluster). How do I know which version I'm printing? And more important, how did you create the module tooth shape? Under "Part Design/Involute Gear"? I found this tutorial which goes through the nitty gritty. https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.fictiv.com%2Farticles%2Fcreating-involute-gears-in-cad&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585b6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751917251001669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=VSEzPKBH8f0nIqyRFjQoiQwoX9%2Bqx2x9FW%2FwFihGqmo%3D&reserved=0 John > -----Original Message----- > From: Todd Zuercher [mailto:to...@pgrahamdunn.com] > Sent: December-15-21 6:32 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Harmonic Drive > > No reason, just picked a number, and that looked good to me. > > Which version are you trying to print? The ones with equal ring > diameters and fudged module, or the one with proper module but differing > diameters? > > Curious to hear how it works, and how strong it may or may not be. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -----Original Message----- > From: John Dammeyer < <mailto:jo...@autoartisans.com> > jo...@autoartisans.com> > Sent: Tuesday, December 14, 2021 6:53 PM > To: 'Enhanced Machine Controller (EMC)' < > <mailto:emc-users@lists.sourceforge.net> > emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Harmonic Drive > > [EXTERNAL EMAIL] Be sure links are safe. > > I've opened it in FreeCAD. Exported the pieces as STEP files and imported > those into AlibreCAD. I added holes in each pinion gear > so that they can be screwed together. I've sliced it to sit on a 6 layer > raft so that the teeth on the glass sided aren't all distorted. > > Time to print will be about 3 hours. Any reason why they are 20mm thick? > Just for strength/power? > > The two outer ring gears got 12 holes on a 70mm radius. For some > reason AlibreCAD shows the 12 holes on the sketch but the extrude cut leaves > out a couple. I've posted a help request on that. > > The ring gears (0.3 mm layers) with a raft take over 5 hours, over 4 without > the raft. > > I've started printing the two pinions. See what they look like. Then > decide about the ring gears. Maybe print one to see how the pinions fit. > Then look at the other ring gear and two more pinion sets. And obviously > will also have to design the pinion drive shaft. > > I imagine the assembly will end up looking something like the one that Sam > built as a dual spline harmonic? > > John > > > > -----Original Message----- > > From: Todd Zuercher [ <mailto:to...@pgrahamdunn.com> > > mailto:to...@pgrahamdunn.com] > > Sent: December-14-21 11:40 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Harmonic Drive > > > > It is a Freecad file, you have to open it with Freecad. (If I > > double click on it in a file manager on a Linux pc I get that list > > to.) > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -----Original Message----- > > From: Gene Heskett < <mailto:ghesk...@shentel.net> > > ghesk...@shentel.net> > > Sent: Tuesday, December 14, 2021 1:53 PM > > To: <mailto:emc-users@lists.sourceforge.net> > > emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Harmonic Drive > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > On Tue, 14 Dec, 2021 at 1:07 PM, Todd Zuercher < > > <mailto:to...@pgrahamdunn.com> to...@pgrahamdunn.com> wrote: > > > > > > To: enhanced machine controller (emc) The "pinned" pinions are for > > if they are to be conventionally made metal gears to accommodate easy > > conventional manufacturing. > > If they were printed, they could simply printed as one piece. A > > metal set of gears would have be hobbed separately, then stacked and > > offset at the correct angles then drilled and pinned together so > they turn as one gear. > > > > Playing with the cad some more I'm not even sure that it would even > > be necessary to fudge the modulus on the ring gears to make them > > both the same diameter. But it comes at the cost of getting the > > highest possible gear reduction. It is only 1.5 tooth/rev instead > > of 1 tooth, but it is still better than the 2 tooth/rev max possible > > with the true harmonic drives. (Although a true harmonic drive can > > get away with and probably works better with finer/smaller teeth.) > > For example if the fixed ring gear has 100 teeth, meshing with 3 > > pinions of 40 teeth on the driven spider. (see attached pic) Then > > on the output side adding one tooth to the ring gear(101) and > > pinions(41) The teeth still mesh perfectly at the same spider axel > > lengths. Then pin the 40 and 41 tooth pinions together. I think > > the final drive ratio would be 67-1/3:1. One revolution of the > > spider would turn the pinions 2.5 times, and advance the driven ring > > gear > > 1.5 teeth. (please correct me if I'm wrong in my calculations.) Also > > I think making the output ring and pinions one tooth smaller instead > > of larger keeps the ratio the same but reverses the output > direction. Here is a link to the Freecad model. > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fd > > riv> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdr > > iv > > e.google.com%2Ffile%2Fd%2F1QX6cw-&data=04%7C01%7Ctoddz%40pgraham > > du > > nn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c573f47cebee96c3e > > 08 > > 06fb43%7C0%7C0%7C637751228834141105%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi > > MC > > 4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000& > > sd > > ata=0p%2F4ye8YsxbrOGDldiclmTE%2FA88AzyMtTAl2W9jekIg%3D&reserved= > > 0 > > zHwiRNLSGqVZV_AoieQYPtvKRB%2Fview%3Fusp%3Dsharing&data=04%7C01%7 > > Ct > > oddz%40pgrahamdunn.com%7C5ce70ebbb > > 0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7 > > C6 > > 37751048404394852%7CUnknown%7CTWFp > > bGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6 > > Mn 0%3D%7C3000&sdata=h1ePHRAQKLaTDCRls > > HUxq3ODzsXgQAQEDzGg3nCfPyY%3D&reserved=0 > > > > > > > > This doesn't render here Todd, its a text list of colors. > > > > > > Making the difference between driven and output two teeth, still works out > > to mesh correctly but makes the output ratio 34:1. > > (100t/40t:102t/42t) Which I think might be about the perfect ratio > > for the rack and pinion drive on my router (to replace it's barely > > adequate 10:1 belt.) However I'd probably be better off simply > > buying a readily available off the shelf 30:1 planetary gear box for > that. > > > > > > > > Were I to do that idea in openscad, I'd union the two different pinions and > > print 4 of them. > > Not having access to your model, probably a mimetype error here, do > > you have an axle bearing per gear, or could I just use one gear per > > unionized pair? It seems to me that both bearings would be > needed to resist the twisting moment on the pinions under load. > > I've now installed freecad, and will dl the link and see if that will show > > me what you have. > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -----Original Message----- > > From: John Dammeyer > > < <mailto:jo...@autoartisans.com%3cmailto:jo...@autoartisans.com> > > jo...@autoartisans.com<mailto:jo...@autoartisans.com>> > > Sent: Tuesday, December 14, 2021 12:30 AM > > To: 'Enhanced Machine Controller (EMC)' > > <emc-users@lists.sourceforge.net<mailto:emc-users@lists.sourceforge. > > ne > > t>> > > Subject: Re: [Emc-users] Harmonic Drive > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > Todd, > > I'm not sure I 'get' how it works with the pinned gears. > > > > I built a different kind of flex cup drive based on a paper on what > > is called an HGD_EWG_Drive > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww. > > geartechnology.com%2Fissues%2F1013x%2Fharmoni&data=04%7C01%7Ctod > > dz > > %40pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c573f > > 47 > > cebee96c3e0806fb43%7C0%7C0%7C637751228834141105%7CUnknown%7CTWFpbGZs > > b3 > > d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D > > %7 > > C3000&sdata=VOwRT5Ol5WFCP9lJXpronQGU6KEJd6R5OoaBRHLzFHk%3D&r > > es > > erved=0 > > c_drive.pdf&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d > > 14 3330dd508d9bf32e1f5%7C5758544c573f47c > > ebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb > > 3d > > 8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM > > zIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=sqS9DyYADHEEp2K6X > > U9 8Jl%2FtEHd%2FuVsehu7vaajW8Fk%3D&r > > eserved=0 > > > > Here's a really short video of the version of one I created. I used > > that earlier 3D print harmonic drive for the base tooth form > > although this type looks like you can use involute profile or even belt > > profile as the flex teeth follow a circular rather than elliptical gear. > Something to play with now that I have some PETG. > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fy > > out> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyo > > ut > > u.be%2Flb6shTgQ1wY&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C48cd > > 05 > > 236af94274e3a408d9bf5d17c0%7C5758544c573f47cebee96c3e0806fb43%7C0%7C > > 0% > > 7C637751228834141105%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ > > QI > > joiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=RhWq7Ob1O > > tP > > w7ewh%2FjHitjP1dGV2oyn0BlV59D5nwVQ%3D&reserved=0 > > %40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f > > 47 > > cebee96c3e0806fb43%7C0%7C0%7C637751 > > 048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > > uM zIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C > > 3000&sdata=L1ZCbk4vQLNwth%2BjgY7JpQQh1a6LD9UN6ePO7Kk5Z2o%3D& > > re > > served=0 > > > > I really need to bring in a bigger stepper to play with this. The > > surplus unit with about 1A at 36V will stall if I even look at it cross > > eyed. > > > > Here's the original I was playing with along side the new one. > > > > <https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fww > > w.a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585 > > b6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751 > > 917251001669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=1IrA7KzaMPq1nzE > > 7D79mP0oW2rkHmTGLDVzWKWLkXJ8%3D&reserved=0> > > https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585b > > 6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377519 > > 17251001669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu > > MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=1IrA7KzaMPq1nzE7 > > D79mP0oW2rkHmTGLDVzWKWLkXJ8%3D&reserved=0 > > utoartisans.com%2Fharmonicdrive%2FHarmonicDrive&data=04%7C01%7Ct > > od > > dz%40pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c57 > > 3f > > 47cebee96c3e0806fb43%7C0%7C0%7C637751228834141105%7CUnknown%7CTWFpbG > > Zs > > b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0% > > 3D > > %7C3000&sdata=DngsWxx6Z9c79ch3EMu1f5P4lcHBY8yqyeRz3zOEeuY%3D& > > ;r > > eserved=0 > > - > > 35.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d14333 > > 0d d508d9bf32e1f5%7C5758544c573f47cebee > > 96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8e > > yJ > > WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLC > > JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ee87%2FTZuN1zEfVCblcYS > > Cn xYyJhVwGscGNyrzoy5M%2Bs%3D&reser > > ved=0 > > > > I still don't have the right size bearings but did have these tiny > > ones I bought 20 years ago at a model aircraft show in the UK. So I > > created bearings that were 22mm diameter. Big issue there > they were really only 21.3mm after printing and that caused all sorts > of > > issues because I forgot that detail. I then printed some oversize, > > created an arbor for them on the lathe and turned them down to > > 22mm. Now I get 100% connection and zero backlash. This things > > spins so smoothly just by placing a finger on the wave cup driver and > > pushing it around. And you can't hold onto the output. > > > > > > <https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fww > > w.a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585 > > b6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751 > > 917251001669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=1IrA7KzaMPq1nzE > > 7D79mP0oW2rkHmTGLDVzWKWLkXJ8%3D&reserved=0> > > https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585b > > 6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377519 > > 17251011659%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu > > MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=jHQryztFJneDoTyU > > SfrBmmSSp6XTVc%2Bq5gM4p6duZlc%3D&reserved=0 > > utoartisans.com%2Fharmonicdrive%2FHarmonicDrive&data=04%7C01%7Ct > > od > > dz%40pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c57 > > 3f > > 47cebee96c3e0806fb43%7C0%7C0%7C637751228834141105%7CUnknown%7CTWFpbG > > Zs > > b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0% > > 3D > > %7C3000&sdata=DngsWxx6Z9c79ch3EMu1f5P4lcHBY8yqyeRz3zOEeuY%3D& > > ;r > > eserved=0 > > - > > 29.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d14333 > > 0d d508d9bf32e1f5%7C5758544c573f47cebee > > 96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8e > > yJ > > WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLC > > JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=98y0KPsDgP0XL%2FwerNJs > > D4 C0iXkSYx3PIXPoI%2FNy1WU%3D&reserv > > ed=0 > > > > And here's a diagram of most of the bits and pieces. > > > > <https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fww > > w.a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585 > > b6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751 > > 917251011659%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=jHQryztFJneDoTy > > USfrBmmSSp6XTVc%2Bq5gM4p6duZlc%3D&reserved=0> > > https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .a%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C42c03c6c9ed34585b > > 6bb08d9bffd5ec7%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377519 > > 17251011659%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu > > MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=jHQryztFJneDoTyU > > SfrBmmSSp6XTVc%2Bq5gM4p6duZlc%3D&reserved=0 > > utoartisans.com%2Fharmonicdrive%2FHarmonicDrive&data=04%7C01%7Ct > > od > > dz%40pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c57 > > 3f > > 47cebee96c3e0806fb43%7C0%7C0%7C637751228834141105%7CUnknown%7CTWFpbG > > Zs > > b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0% > > 3D > > %7C3000&sdata=DngsWxx6Z9c79ch3EMu1f5P4lcHBY8yqyeRz3zOEeuY%3D& > > ;r > > eserved=0 > > - > > 28.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d14333 > > 0d d508d9bf32e1f5%7C5758544c573f47cebee > > 96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8e > > yJ > > WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLC > > JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=rdvZ%2B4gMMR8YZX4iZCMJ > > nZ > > QY41q82NsnTQCCcG8%2Faw4%3D&re > > served=0 > > > > The main bearings are utility trailer 1" ID roller bearings. I'm > > waiting for 6101 and 6103 bearings to arrive. Most of the parts will be > > made from metal. > > > > John Dammeyer > > > > > > > -----Original Message----- > > > From: Todd Zuercher > > > [ <mailto:to...@pgrahamdunn.com%3cmailto:to...@pgrahamdunn.com%3e> > > > mailto:to...@pgrahamdunn.com<mailto:to...@pgrahamdunn.com>] > > > Sent: December-03-21 8:37 AM > > > To: Enhanced Machine Controller (EMC) > > > Subject: Re: [Emc-users] Harmonic Drive > > > > > > It was easier to model in Freecad than I expected. I'll try to attach a > > > jpg of it and see if it goes through. > > > > > > And if it doesn't go through a link to it on my Google drive. > > > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2 > > > Fdr> > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2F > > > dr > > > iv > > > e.google.com%2Ffile%2Fd%2F1_eSu-olALMsevTnOpzQ1o1r_rPjfexwU%2Fview > > > %3 > > > Fu > > > sp%3Dsharing&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebb > > > b0 > > > d1 > > > 43330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C > > > 63 > > > 77 > > > 51048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjo > > > iV > > > 2l > > > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=kFLK8IVVRbugQ > > > ye > > > Ts > > > Zl77AYP%2BQsgwBuVgrvUjR9ysb4%3D&reserved=0 > > > > > > Here is a link to the Freecad file (Freecad v0.18). > > > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2 > > > Fdr> > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2F > > > dr > > > iv > > > e.google.com%2Ffile%2Fd%2F1GGwG9nzmYowKeuMAWMvOExeGrvSzZCnY%2Fview > > > %3 > > > Fu > > > sp%3Dsharing&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebb > > > b0 > > > d1 > > > 43330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C > > > 63 > > > 77 > > > 51048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjo > > > iV > > > 2l > > > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=GePtOJMld%2Fr > > > rT > > > Nk > > > HQTQRqAUXh6OWIGDv8Ry8p2%2FoMTo%3D&reserved=0 > > > > > > > > > Todd Zuercher > > > P. Graham Dunn Inc. > > > 630 Henry Street > > > Dalton, Ohio 44618 > > > Phone: (330)828-2105ext. 2031 > > > > > > -----Original Message----- > > > From: Andy Pugh < > > > <mailto:bodge...@gmail.com%3cmailto:bodge...@gmail.com> > > > bodge...@gmail.com<mailto:bodge...@gmail.com>> > > > Sent: Thursday, December 02, 2021 6:40 PM > > > To: Enhanced Machine Controller (EMC) > > > <emc-users@lists.sourceforge.net<mailto:emc-users@lists.sourceforge. > > > ne > > > t>> > > > Subject: Re: [Emc-users] Harmonic Drive > > > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > > > > On 2 Dec 2021, at 21:14, Todd Zuercher < > > > > <mailto:to...@pgrahamdunn.com%3cmailto:to...@pgrahamdunn.com> > > > > to...@pgrahamdunn.com<mailto:to...@pgrahamdunn.com>> wrote: > > > > > > > > What if you used two outer ring gears of the same diameter one > > > > with one fewer teeth. Then have 4 sets of planetaries stacked > > > > in > > > pairs. Each pair would be pinned together > > > > > > You can just use pinions twice as long as the ring gears. I think > > > I have seen this done > > > > > > It would work with all-external gears too. > > > > > > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > > > > <mailto:Emc-users@lists.sourceforge.net%3cmailto:Emc-users@lists.s > > > ourceforge.n> > > > Emc-users@lists.sourceforge.net<mailto:Emc-users@lists.sourceforge > > > .n > > > et > > > > > > > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2 > > > Fli> > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2F > > > li > > > st > > > s.sourceforge.net%2Flists%2Flistinfo%2Femc-&data=04%7C01%7Ctod > > > dz > > > %4 > > > 0pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f > > > 47 > > > ce > > > bee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZs > > > b3 > > > d8 > > > eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D > > > %7 > > > C3 > > > 000&sdata=pqeO%2FLq%2FcybqqS5iWHkNI2aKp%2BeQi12xvTnziOJVgJA%3D > > > &a > > > mp > > > ;reserved=0 > > > users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7Ce891b8fadd88429 > > > 7a > > > 79 > > > 608d9b5ed4669%7C5758544c573f47cebee9 > > > 6c3e0806fb43%7C0%7C0%7C637740852975732935%7CUnknown%7CTWFpbGZsb3d8 > > > ey > > > JW > > > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ > > > BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=16s%2BM61vPdzTAtr3Qg6 > > > tt Yn RU6%2Fg4vkOsrYcbPRxmuY%3D&reserv > > > ed=0 > > > > > > > > _______________________________________________ > > Emc-users mailing list > > > > <mailto:Emc-users@lists.sourceforge.net%3cmailto:emc-us...@lists.sou > > rceforge.net> > > Emc-users@lists.sourceforge.net<mailto:Emc-users@lists.sourceforge.n > > et > > > > > > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl > > ist> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fli > > st > > s.sourceforge.net%2Flists%2Flistinfo%2Femc-&data=04%7C01%7Ctoddz > > %4 > > 0pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c573f47 > > ce > > bee96c3e0806fb43%7C0%7C0%7C637751228834151099%7CUnknown%7CTWFpbGZsb3 > > d8 > > eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7 > > C3 > > 000&sdata=qAc5EddzjCwZp6n38C6Ak5VpVHSeIiOFmxpylPic%2Fsc%3D&r > > es > > erved=0 > > users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330 > > dd > > 508d9bf32e1f5%7C5758544c573f47cebee9 > > 6c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8ey > > JW > > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ > > BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=G2%2BTBO5nRNBAppBprf6PD > > t% > > 2FR8nCJRCruQMI6o5%2FbeVY%3D&r > > eserved=0 > > > > _______________________________________________ > > Emc-users mailing list > > <mailto:Emc-users@lists.sourceforge.net> > > Emc-users@lists.sourceforge.net > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl > > ist> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fli > > st > > s.sourceforge.net%2Flists%2Flistinfo%2Femc-&data=04%7C01%7Ctoddz > > %4 > > 0pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c573f47 > > ce > > bee96c3e0806fb43%7C0%7C0%7C637751228834151099%7CUnknown%7CTWFpbGZsb3 > > d8 > > eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7 > > C3 > > 000&sdata=qAc5EddzjCwZp6n38C6Ak5VpVHSeIiOFmxpylPic%2Fsc%3D&r > > es > > erved=0 > > users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330 > > dd > > 508d9bf32e1f5%7C5758544c573f47cebee9 > > 6c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8ey > > JW > > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ > > BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=G2%2BTBO5nRNBAppBprf6PD > > t% > > 2FR8nCJRCruQMI6o5%2FbeVY%3D&r > > eserved=0 > > > > > > _______________________________________________ > > Emc-users mailing list > > <mailto:Emc-users@lists.sourceforge.net> > > Emc-users@lists.sourceforge.net > > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl > > ist> > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fli > > st > > s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7C > > to > > ddz%40pgrahamdunn.com%7C48cd05236af94274e3a408d9bf5d17c0%7C5758544c5 > > 73 > > f47cebee96c3e0806fb43%7C0%7C0%7C637751228834151099%7CUnknown%7CTWFpb > > GZ > > sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0 > > %3 > > D%7C3000&sdata=k67NThmBsFQoqonsx%2ByC1Kd1jXrHcE%2F9R9U6EmlizIM%3 > > D& > > amp;reserved=0 > > > > _______________________________________________ > Emc-users mailing list > <mailto:Emc-users@lists.sourceforge.net> > Emc-users@lists.sourceforge.net > <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flis > ts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Ct > oddz%40pgrahamdunn.com%7C42c03c6c9ed34585b6bb08d9bffd5ec7%7C5758544c57 > 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