On Thursday 21 December 2017 12:39:16 Chris Albertson wrote: > On Thu, Dec 21, 2017 at 2:12 AM, Gene Heskett <[email protected]> wrote: > > On Thursday 21 December 2017 04:18:46 Chris Albertson wrote: > > > To make this really work for rotary tables you need a very fine > > > pitch. I have seen these 3D printed in plastic but they slip and > > > don't handle much torque because the outer ring deforms > > > One idea I had was to press fit the plastic ring gear into a short > > > section of steel pipe. > > > > > > Put you can buy these drives already made for about $250. That > > > is really not abad price for arc-second level precision and near > > > zero backlash. > > > > Where? > > I wrote that before I figured out how to see the video. On eBay you > can fin harmonic drives. They do the something(roughly 1:100 > reduction) but actually better accuracy. > Here are a few: ebay.com/sch/i.html?_nkw=harmonic+drive... > <https://www.ebay.com/sch/i.html?_nkw=harmonic+drive&_in_kw=1&_ex_kw=&; >_sacat=0&_mPrRngCbx=1&_udlo=50&_udhi=275&_ftrt=901&_ftrv=1&_sabdlo=&_sa >bdhi=&_samilow=&_samihi=&_sadis=15&_stpos=90278&_sargn=-1%26saslc%3D1&_ >salic=1&_sop=12&_dmd=1&_ipg=50>
All but 1 in that 3 page list do not give a list of dimensions, 2 - 4 others only list as needing an 8mm drive end input. Many are obviously incomplete even, I certainly cannot come to any conclusion as to whether or not I could use one of them in on my small mill with its limited Z overhead. One outfit even goes so far as to show us 3 warehouse racks full of boxes, as if we could blow the pix up and see what the box says on it. And the $170 version seems to be guts only, without the internal rack. Maybe I'm to be considered dumb because I don't know them from long familiarity with using them, but so is assuming everyone has a pile of makers catalogues reaching back 30 years so we can look it up by the part number. Sheesh. I will say thank you Lawrence, specifically for the code you carved a lathe encoder wheel with all those years ago. I've rearranged it some, and adjusted the sizes and slot counts, and made a few disks from it myself. The one on TLM is about as small as it can be and still be functional. I lost another 1/2" of OD trying to fit it into a G0704, and just replaced its a/b signals with a 1000 line omron on the rear of the motor. The index I still get from the disk on the spindle. Thank you for the loan of that code from the wiki. > > > On Wed, Dec 20, 2017 at 10:15 PM, Lawrence Glaister > > > <[email protected]> > > > > wrote: > > > > very cool Gene.... had some troubles playing the video, but I > > > > seem to have the gist of it. It does seem like a very > > > > interesting design for rotary tables.... just have to figure out > > > > how to re-purpose some rear end ring gears and pinions.... > > > > hmmm... was thinking of regearing the jeep anyway!. Lawrence > > > > Glaister VE7IT > > > > Now theres a recipe for some bigger machinery, > > Maybe a better source of parts would be a Toyota Prius viable ratio > transmission. It is already set up with planet gears that match the > ring. The parts come off without even needing tools. > See the ring and planet gear on the left and center of this video. > Junk yard price is about $300. Also notice the two electric motors. > They could like be repurposed. Link? > > -- > > Chris Albertson > Redondo Beach, California > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
