Ha ha, oops, they're in the UK On Tue, 13 Apr 2021 at 17:22, Roland Jollivet <roland.jolli...@gmail.com> wrote:
> > Did you try PGM Reball (saw them on an old video I have) > > > On Tue, 13 Apr 2021 at 14:38, Todd Zuercher <to...@pgrahamdunn.com> wrote: > >> Yes, near the limit switch, outside of the normal travel area, I can not >> measure any backlash. That pretty much points the finger squarely at wear >> on the screw as the main culprit. I think I have figured out the "springy" >> backlash uptake mystery. It is simply the weight of the screw sagging down >> and resting on the nut pushing the table to the center of the ball grooves >> (remember the screw is more than 14ft long.) >> >> Anyone know of any good ball-screw refitters in the States? I already >> checked with one and they didn't want to touch it. >> >> Todd Zuercher >> P. Graham Dunn Inc. >> 630 Henry Street >> Dalton, Ohio 44618 >> Phone: (330)828-2105ext. 2031 >> >> -----Original Message----- >> From: Stuart Stevenson <stus...@gmail.com> >> Sent: Monday, April 12, 2021 11:12 PM >> To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> >> Subject: Re: [Emc-users] Worn Ball Screw? >> >> [EXTERNAL EMAIL] Be sure links are safe. >> >> 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 <el...@pico-systems.com> 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 >> > Emc-users@lists.sourceforge.net >> > 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 >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
