On Monday 10 September 2018 03:52:23 Chris Albertson wrote: > The lasers are easy to find on Amazon but be warned the laser is not > perfectly aligned with the housing. But as I said, this does not > matter if you spin the spindle. > > I think a laser is the only option. If you are measuring the bed > your reference needs to be at least 10X straighter then the bed. > Precsion rods are not good enough but a $20 laser is literally perfect > (as long as you rotate the spindle.) > > With effort you can use the same laser to measure the error with the > lead screw pitch. Use it as a laser range finder or laser inferometer > > But all this measurement may be moot if the lathe is not reputable. > The error might be random. Maybe the carriage moves like a tuck on a > dirt road?
So far, it seems the wear is pretty well confined to the first 6", by the time thats been reached the measured offset doesn't seem to change with direction of carriage motion. Backlash of x is in the 2.1 thou range as its a ball screw with a slight preload in the thrust bearing, as is the much larger Z screw, but the backlash there is around 5 thou due to a sloppy thrust bearing. Right at the spindle nose, direction of carriage travel causes about a 3 thou diff, but that gets well by 4" out. It could be a lot worse, and its rather worse on TLM because the head is not well trammed to the bed, the whole head casting has been replaced, and I'll probably eventually do this to it. Shoemakers kids, lack of round tuits and all that... [...] -- 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
