On 06/13/2013 07:22 AM, andy pugh wrote: > On 13 June 2013 14:47, Kirk Wallace <kwall...@wallacecompany.com> wrote: > >> Depending on the thread pitch, there are one or two threads per >> leadscrew revolution. > ... >> The ELS takes the place of the spindle to leadscrew and indicator gearing. > > My point is that the indicator measures the carriage position (modulo > several threads) but an ELS does not know this position. > (If the machine has linear scales, then the problem I am describing > does not exist).
Looking at the Autoartisans ELS the X and Z positions are known by counting steps from touch-off, there is a spindle index and the position is probably interpolated (a la Mach). > And there are many thread pitches where you can't use a threading > indicator anyway (cross-standard threads with the 127 tooth gear, for > example) > > I worked out all the change-gear settings for my Chinese lathe (before > I thought of doing CNC). There are actually several changewheel > combinations per pitch, but on that lathe 1.2mm pitch couldn't be > disenaged. > The summary table is on sheet 3 here, the workings on the other > sheets: > https://docs.google.com/spreadsheet/ccc?key=0AhjJW1-T6n7CdFFSbTQwTjFmWlg3ZXVtUnNxSHo0dlE&usp=sharing A limitation might come about if one is tied to the stock gear spider and change set, but as long as there is a ratio between spindle revs to leadscrew revs, there is a gearing of some sort that can provide the ratio. It just seems easier to dust off an old PC and use LinuxCNC. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
