On Tuesday 25 June 2019 10:29:51 andy pugh wrote: > On Tue, 25 Jun 2019 at 14:27, Gene Heskett <ghesk...@shentel.net> wrote: > > Absolutely. And in the ER32's turning 3G's max in my G0704's abused > > spindle, balance is not a prime concern, but in an ER20 where you > > expect to hit perhaps 15k revs, or in my 6040 with its ER11 turning > > 24k, a few milligrams can destroy the motors bearings eventually. > > An ER16 nut is 22mm dia. > > Centrifugal[1] force is MR(omega)^2. > 24k rpm = 2513 rad/sec > So the bearing force on a 24k rpm ER16 is 138N / g.
And that is quite excessive for those sized bearings even if ceramic. Like concrete cracking, the question isn't if, but when. > To put that in perspective, FSWizard suggests settings that give a 30N > cutting force on a 3mm cuttter. > I expect that the oscillatory nature of the centrifugal force gives > the bearings a harder time too. Exactly the point I was trying to make using common sense, but don't have the math to prove it, thank you. > > [1] I have a physics degree, I am licensed to use centrifugal > force[2]. Do not try this at home. > [2] www.xkcd.com/123 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
