On Saturday 08 September 2018 22:03:21 jeremy youngs wrote: > Gene , can you mount a probe on the carriage and probe a lathe > alignment bar ( or drill rod )?
I don't have a probe per sei on it. What I'm doing is sticking a mag base to the top of the toolpost holder base that has replaced the mangled compound, with atm a dial indicator riding a 21" bar of .500 diameter A2 rod. Theres a thou or so wobble right at the er40 adapter, and the center dimple on the other end is off center about 2 thou riding a live center in the tailstock barrel. The A2 is slightly bent so I get about a 10 thou wobble in the middle of it, but with the spindle turning, the true center is easily seen. I have used the lathes x motor to try and straighten it better, but by the time I get enough bow in it to make a diff, the rod shortens and pops the end off the live center. I would do it according to demagnetizeing rules by pushing it far enough to bent it back, with the spindle turning, and once I have evidence that I am actually bending it, the let it run while I slowly back off the push, which should make it run pretty true. But w/o a socket instead of a center in the tailstock, I can't get up enough pressure to actually bend it straight. A half inch of A2 20+ inches long is still pretty strong stuff. I should buy another 36" piece of 3/4" A2 which would obviously be stiffer. But I wouldn't wager it would be straighter. So I'd still have to deal with the wobble. And that much A2 isn't cheap. Setting up a contact probe would trigger on the peaks of the wobble, and that measurement would be meaningless w/o knowing the p-p wobble at each probed point. I can get that accurate with a dial. I think... >From what I have observed so far, I think the huge majority of what I need to correct is in the first 8" from the spindle, the rest looks like a fairly straight line, IF the tailstock is on center. The major error once the sled is pulled to center, is vertical. 50 thou off at least. Thanks Jeremy. > _______________________________________________ > 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
