Chris Reynolds wrote: > In the past whenever I've machined holes they end up not perfectly round. I > wondered if part of that could be because of the backlash compensation or > some other setting that I have. I don't think my machine has that much play > in it that it would cause circles to come out like that. > Well, HOW out of round are they? Typically, you get a 4-lobed pattern, where each quadrant is displaced by a tiny amount. You can see this, or even feel it, with a telescoping hole gauge or inside mike.
Another source of error is orthogonality error, ie. the X and Y axes are not perfectly square to each other. An offshoot of this is "rocking" of the slide. When the leadscrew reverses, the part that slides on the ways rocks slightly, throwing the 2nd axis out of square one way, and then the other. This rocking can often be created with hand force while observing dial indicators, making it a bit easier to detect. Most orthogonality errors will create oval holes, so the two measurements diagonal to the axes will be different. Jon ------------------------------------------------------------------------------ FREE DOWNLOAD - uberSVN with Social Coding for Subversion. Subversion made easy with a complete admin console. Easy to use, easy to manage, easy to install, easy to extend. Get a Free download of the new open ALM Subversion platform now. http://p.sf.net/sfu/wandisco-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
