On Wednesday 26 September 2018 10:59:34 Greg Bentzinger via Emc-users wrote:
> Greg begin > > Am I going to be the 1st person to point out that the tailstock on > most lathe designs does not use the same ways as the lathe carriage > and therefore is not subject to the bed wear issue. No that came to me last Monday night, and I made some measurements based on that yesterday. > If the tailstock > is out it is mal-adjusted or the lathe is not leveled properly and you > have bed twist / slope / rainbow etc. Greg end Not terribly likely. In this case several visible nicks in the inside edge of the front flat it slides on, guided by the back v-way. Judicious use of the dmt plate, wetted with paint thinner to knock off the resultant high spots reduced the error noticeably. I also took a nice whacks high spot off the back v-way itself, in about the middle of its travel. Something had hit the top of the v-way, upsetting the metal on both front and rear faces of it. As far as the lathe bed leveling goes, the Sheldon's nearly all ride the right end of the bed on a simple ball joint, and when moved, its recommended that the preload nut, inside the bed at the right end, be loosened enough to let the ball joint re-adjust itself to the new floor. Thats been done at least twice since it was parked in its present location a bit over 2 years ago. So I am not overly concerned with a poorly poured floor causing bed twist. After this mornings work, the major remaining error is the nearly 4 thou the z screw moves endways because of a poorly fitted thrust bearing. Thats too much backlash to correct with lcnc. And 3x the x backlash. Its a bear to get off to fix the preload which does not now exist. But it will be a good project while I wait for the stuff I ordered last night. I'll have a week to entertain myself before that stuff arrives, by which time I'll have had a couple near beers to celebrate my 84th. :) -- 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
