On Monday 27 February 2017 10:26:31 bari wrote: > On 02/25/2017 05:53 PM, Gene Heskett wrote: > > How much gear mapping does it require to get the same accuracy the > > ball screw can deliver? > > 2 foot or 15 foot long ball screw? :)
1.45 meters in the present case, Bari, and backlash is currently about 7 thou, most (about 5.5 thou) of which is in the poor Chinese thrust assembly bearings at the anchor point. I need to dis it, and put about 3 layers of heavy alu foil between the outer races and the stop ledges. Or if there is a center spacer, thin it on a surface plate. Still beats the band out of the .087" of backlash between the handwheel and any carriage motion it had the day after I unloaded it here. However I don't believe the rack I pried off the bottom of the beds front lip was more than 44" long. I took it off to get room for a wider, full length of the saddle, brass gib strip, which is not now adjustable for clearances, and has about 3 thou of slop if I take a really big prybar to it. With cutting forces normally all downward, and that wide a saddle stance on the bed, any lift is a sign of a tool so dull as to be worthless. Sharpen or replace it is my motto. :) Actually, I have no access to a laser interferometer based measuring facility that could confirm or deny any cyclic non-linearities. Hobbiest, not certification lab tools here at the coyotes den. ;-) Given that I do know how they work, with enough time and sheckel's, I may be able to make one, but at my age and remaining time its not going to happen. I'd druther make swarf to fit right. A decent 1" stroke dial is what serves to calibrate stuff here. 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> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
