For the XY axis: First bore four holes in a rectangle as large as you can make it. You want the rectangle to be close to a square to get the most accuracy from this. Insert dowels into the holes. Now measure the lengths of the diagonals using a caliper if you have one large enough.
If not, take a stick and bore a hole in one end to fit the dowels. Mount the dial caliper on the other end. Use that to measure the difference in length of the diagonals. After that, it's all geometry. The Z axis is a little more complicated because there are two issues: 1 -- Is the spindle perpendicular to the XY plane? 2 -- Is the Z axis travel perpendicular to the XY plane? For the first, mount the indicator on a long arm attached to the spindle. Rotate the spindle by hand and see how the indicator varies. The amount of variation will tell you how far out of square the spindle is. If you plan on drilling holes or milling edges of "square" blocks, it must be accurate. If you are just carving with the end of a ball mill, it might not matter as much. If you are drilling holes, this error cannot be corrected in software. For the second, mount a large cylinder with ends that are perpendicular to the axis on the table (a cylindrical square). Put your indicator on the Z axis and move it up and down, touching the surface of the cylinder. Do this on the edge aligned with the X axis and on the edge aligned with the Y axis. If you don't have such a square, you should be able to make a reasonable one on a lathe. If you don't have a lathe, use a plane square. You should be able to make an accurate square on you router after you correct the XY axis. In principle, misalignment of the axis motion can be corrected in software. Whew. I hope I got all of the details right. If not, someone please correct me. Ken Christopher Purcell wrote: > I would like to improve my home-made 3D wood carving router. It has > stepper-driven 1m long THK ball screws (bless you Ebay) which seem to > be moving exactly as EMC2 commands, now that I have Helical couplers > fixing the backlash. The next thing I want to check and maybe tweak > is the perpendicularity of the 3 axes, which I bolted down using only > a carpenters square and level as guidance. This is in a home wood > working shop so the only instrumentation available is a dial > indicator. If I can measure the axes, then corrections can be included > in EMC, presumably as hinted at in the kinematics chapter of the > Integrators handbook. > > How do you measure the perpendicularity of 3 axes of a mill? > > [EMAIL PROTECTED] > > > > > > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
