I have no experience with this but I've read about people using oversized balls to fix this. I think it is a stop-gap. But you can see how they would ride above the center of the groove and be very solid. They are talking *very tiny* amount of oversize. I seem to remember having to sort the balls using a micrometer.
On Mon, Apr 12, 2021 at 8:14 PM Stuart Stevenson <[email protected]> wrote: > Plus or minus .010 is an amazing amount. Also, you mentioned another area > on the screw you saw .001 lost motion. This leads to a screw problem. > I would do what Jon Elson says as this sounds strange but I would expect to > find screw wear. If it was nut wear the backlash in all areas of the screw > would be close to equal. Not knowing the drive train maybe there is a gear > train and one area of the gear train has worn teeth and where you found > almost no lost motion is where the gear train is the best. > Expect screw wear but hope for a gear train problem. > HTH > Stuart > > On Mon, Apr 12, 2021 at 5:15 PM Jon Elson <[email protected]> wrote: > > > On 04/12/2021 09:48 AM, Todd Zuercher wrote: > > > Those here who have had to deal with a worn out ball screw. > > I'd dig into the works and examine everything. It does NOT > > sound like simple wear. > > The rotating nut likely runs in a pair of either > > angular-contact bearings or tapered roller > > bearings. There will be a preloading arrangement to > > constrain the nut. Also, the > > screw is usually fixed at both ends. If the clamp has > > gotten loose at one or both ends, it could > > allow some flex of the mount under load. Attach a dial test > > indicator to the slide and > > read against the end of the screw, and watch for movement > > when you apply load. > > > > Some old ballnuts were actually TWO completely separate nuts > > that were preloaded against > > each other with Belleville washers. It is possible some of > > the Bellevilles have cracked. > > Also, they often used dowel pins to align the two nuts > > rotationally. If one of the dowels has > > cracked, that could cause this kind of issue. > > > > Jon > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > Addressee is the intended audience. > If you are not the addressee then my consent is not given for you to read > this email furthermore it is my wish you would close this without saving or > reading, and cease and desist from saving or opening my private > correspondence. > Thank you for honoring my wish. > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
