On Tuesday 25 September 2018 11:35:18 Jon Elson wrote: > On 09/25/2018 03:02 AM, andy pugh wrote: > > I can't help thinking that the way to determine the amount of > > correction needed is to actually machine a test bar and measure it. > > The problem here is that deflection of the bar, and also the > lathe, will affect the accuracy of the result. > You can't turn between centers, or at least that adds a > whole new dimension to possible errors. > If you know that you turn the same diameter at each end, > then maybe turning the whole length will give a profile of > the bed. But, then, diameter errors on the test bar could > be pure shift in the X axis, or some combination of that > plus a rolling of the carriage due to height differences on > the two ways. > > Having (painstakingly) redone a lathe bed, it is more > complicated than at first glance. > Understatement of the year, Jon. :)
> My preference is to use a hardened and ground bar of known > straightness, held just in the spindle, and a sensitive > indicator to ride up and down the length of it. > > Jon > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > 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> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
