Be careful here, the bearings purchased are BE CB P. The CB denotes an axial CLEARANCE class of bearing i.e. http://www.skf.com/skf/productcatalogue/jsp/viewers/tableViewer.jsp?tableName=1_3_t1&maincatalogue=1&lang=en
If you want preload then you new universally matched pairs (+ lots more $) which are marked with GA GB or GC depending on preload i.e. http://www.skf.com/skf/productcatalogue/jsp/viewers/tableViewer.jsp?tableName=1_3_t3&maincatalogue=1&lang=en GA, GB, GC bearings don't need shims as they are ground to produce the correct preload. With type CB bearings you need a spacer between the bearings and then some method of applying the preload, i.e. tighten by "feel", wave washer etc. Hope this helps. -------------------------------------------------- From: "Jan de Kruyf" <jan.de.kr...@gmail.com> Sent: Thursday, November 03, 2011 4:08 PM To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] OT, Ball screw bearings, preload > Hallo, > look at the picture quickly: > > http://www.skf.com/skf/productcatalogue/jsp/viewers/tableViewer.jsp?tableName=1_3_t3&maincatalogue=1&lang=en > > the left side picture is normally the situation when there is a big nut on > the shaft to hold the bearing in place. This nut either has a counter-nut > to lock it or it is of a special construction so it can be secured. If > this > is the case then make sure the nut-face that holds the brearings is > perfectly flat and square. > The right picture is the case when the outerrings need compressing by a > specially made ring (again perfectly flat and square). The shaft locknut > does not need to be quite as perfect in that case. > > In both cases the object of the exercise is to close the natural gap > between the rings. This will give the bearings just the right preload. > > j. > > > > On Wed, Nov 2, 2011 at 6:02 PM, Bruce Klawiter <bmkl...@yahoo.com> wrote: > >> I bought new bearings for the ball screws on my mill, SKF 7204 BECBP. >> >> http://www.skf.com/skf/productcatalogue/Forwarder?action=PPP&lang=en&imperial=false&windowName=null&perfid=123002&prodid=1230020204 >> >> I have read conflicting information on how to install them. >> It appears the best way would be installing them back to back, but I have >> read the inner rings should be clamped tight and also read the outer >> rings >> should be clamped tight when there back to back. >> >> I am not sure I understand the proload either and can't decipher what it >> is form the SKF website. >> >> This is what I think I need to do, find what the preload is (weight) and >> measure the defection of the outer race when this weight is placed on the >> bearing. >> >> Take this measurement X 2 and shim between the the races of the two >> bearings and clamp tight the inner rings and I will have the correct >> preload. >> >> Do I have this right. >> How do I find the preload >> >> Your help is greatly appreciated, >> Bruce >> >> >> ------------------------------------------------------------------------------ >> RSA® Conference 2012 >> Save $700 by Nov 18 >> Register now! >> http://p.sf.net/sfu/rsa-sfdev2dev1 >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ------------------------------------------------------------------------------ > RSA(R) Conference 2012 > Save $700 by Nov 18 > Register now > http://p.sf.net/sfu/rsa-sfdev2dev1 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
