On Monday 16 December 2019 14:06:57 andy pugh wrote: > On Mon, 16 Dec 2019 at 17:21, Gene Heskett <ghesk...@shentel.net> wrote: > > I see that the worm drive that indexes this thing is not in the > > base, but in the part that tilts. > > It has to be, surely? I can't see how you could tilt the worm and not > move the shaft. > Of course. but the pix make that hard to discern.
> > This throws a large monkey wrench into my plans to belt drive the > > worm from a motor on the rear of the base as the shaft spacing would > > then change with an adjustment of the tilt. > > Did you see how I modified mine? > https://www.cnczone.com/forums/uncategorised-metalworking-machines/172 >314-cnc.html No, but the lack of a geardown makes the step a major portion of the error, whereas the use of a much smaller stepper with 8/1 or better on that proposed center shaft should turn the steps so slow as to have the steps disappear into the general mechanical noise. I have one nema 23 motor, a 225oz/in I'll try to put on the 6040's Z, and take that even smaller motor to run this. Thanks for that link. I think I can do that hex boreing on the sheldon in backgear if I do it direct. But I like my idea better if I can work out the sizes And eccentricity in the bull is that main reason I want to try this. My motorized 4" has tight spots and loose spots with a degree plus of backlash in some places, a very poorly made POS from India. Haveing seen an 8" quality made table that had a very consistent and vanishingly small backlash, I am hoping some of that might be in the price, but this has lots of toys to eat that up. I've not been able to pick it up and play with it yet to find out. The bare head, minus chuck and plates, cranks etc, is 57 kg. I got it from the carton laying on a 2 wheeler to just inside the garage door, 2 feet maybe but thats as far as my back can do. > > Any method of fixing the motor to it must then move the motor with > > the tilt. And it must clear the base as it tilts. > > It might actually be better to ditch the worm and wheel, and to drive > the spindle from the back through a large belt reduction. Not possible as the stuff will hit the base or the table before the tilt has reached 5 degrees. > Before you go any further, test the backlash at all positions around > the spindle rotation and make sure that it is possible to adjust the > worm engagement to be free-turning and low-backlash at all positions. > > My BS0 clone was always too tight at the tightest spot and too loose a > the loosest spot. > > I wonder if the BS0 body is large enough to serve as a mounting for > https://www.ebay.com/itm/163654248380 > (Which is an integrated servo, harmonic drive and cross-roller > bearing) Doubtfull. Great idea though, zilch backlash. Thanks Andy. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
