Abstract
When we try to measure the run out accuracy of a tool machine spindle, we generally use both a sophisticated polished sphere as a roundness master and a condenser type probe, then we make the machine spindle rotate and we measure the master sphere surface run out attached to the spindle. This data contain not only spindle run out error but also sphere profile error. We apply multi step point method for the purpose of separation of run out error and sphere profile error. Co-axiallity; Run out center of the spindle and the center of a master sphere should be coincident almost perfectly, otherwise complete and accurate separation by the multi step method will not be applicable. We applied a newly developed two dimensional adjusting instrument on which the upper mentioned master sphere is located. This instrument consists of 4 smaller diameter columns and 1 bigger one. Bigger cylinder is elastically bent first by 4 bolts screws, then four columns deforms, too. Two reductions of bolts displacement has been done by these columns. Now it is possible to adjust the sphere center within a few or less than 1μm. We make sure the spindle run out is 1.3〜1.2μm and the sphere profile is 3.8〜3.9μm respectively within 0.1μm repeatability.
