On Fri, Dec 17, 2021 at 6:05 PM Sam Sokolik <samco...@gmail.com> wrote:
> Hmm - seems we are making things a bit more complicated than they need to > be.. Why didn't the simple flex gear work ok? You need to make the > system with fine enough splines that the flexure is at a minimum... You > can lower the backlash to a minimum by applying a small amount of > pressure to the system. > The problem with small splines is that he is making this with printed plastic. There is a minimum feature size that works. Seriously you want to stay above module 0.5 and bigger if you can. Mod 1.0 is more realistic There are two reasons. (1) plastic is not very strong unless you make the parts big and (2) the printer makes parts with dimensional tolerances of about 0.4 mm so if your parts have 1mm features you can expect 50% dimensional errors. That said, modulo 1.0 gears work really well. Smaler ones have a short life. Finally ANY flexing at all is the death of printed parts. They fail by the failure of interlayer adhesion. Think of printed plastic like it is soft pine wood. When making gears from yellow pine, the direction of the grain matters a lot and no one would think of making module 0.5 gears with pine. I've been able to build an entire CNC conversion kit for a mini-mill from printed plastic. The stuff is VERY rigid and strong if you make the parts large enough > > sam > > On Fri, Dec 17, 2021 at 7:46 PM John Dammeyer <jo...@autoartisans.com> > wrote: > > > Alright. So it spins really freely but keeping the planetary cluster > > centred is a bit of an issue. So the attached photo shows roughly (very > > roughly) what I had in mind. > > > > With the right coupler between the motor and the gear cluster the > > planetary assembly should stay in the same place. There really isn't any > > axial load. There is a place for a 40mmx19mm bearing that I happen to > have > > on hand. > > > > But what about the driven ring gear? In one of the model shops today I > > saw a package of 100 5.5mm stainless steel balls they sell for putting > into > > paint bottles to help mix them up. > > > > Seemed and ideal size for a bearing race between the two ring gears. > Kind > > of like what Gene H. stated he did on his setup. (Pictures?) So the > Blue > > Gear is fixed. The Green Rotates. The lazy susan like bearing between > > handles axial pressure in the direction of the blue gear. But really the > > only thing holding up the green ring gear is the planetary assembly. > > > > Say we wanted to mount a face plate or chuck onto the green gear. I'm > > open to ideas on how to stabilize that. Sketches would be great. > > > > Methinks a part that surrounds the blue gear and extends over the green > > and they also have a bearing race between. Or we make a similar bearing > > mount to the rear one for the front with the gear cluster holding this in > > place extended out to the bearing. Now the faceplate is attached to > this. > > But a lot more axial twist on the small bearing in the middle. > > > > Thanks > > John > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
