Comparison of indexing tables, with small angle devider
Project Description
SMD will restart its activities for a CMC entry for calibration of indexing tables and polygons. One of the important aspects of proving the capability for these calibrations and for validating the calibration methods is obtaining good results in international comparisons. BNM-LNE is prepared to give help by participating in a bilateral comparison which will thus support the MRA (CMC).
Two indexing tables are provided by SMD. The first one is a Moore 1440, standard version. The second one is a Moore 1440 with a supplementary small angle divider.
Final Report 2013-10-09
The comparison was set up to evaluate if this type of calibration is performed correctly by SMD. The project was completed in 2012 and the results show good agreement for the fixed positions of one of the indexing tables. For the other one, there were 2 out of 24 results with En values between 1 and 1,5. For the small angle devider, the overall profine of the deviations and the hysteresis between the clockwise and anti-clockwise rotations of the small angle devider micrometer screw agree between LNE and SMD, but the slope is different, so that most of the En values are > 1 (up to 3,7). The reason for that could not be found. It has to be taken in mind that the small angle devider and its indexing table had to be repaired between the measurements at LNE and those at SMD.
Progress Report 2003-10-31
Two indexing tables are provided by SMD. The first one is a Moore 1440, standard version. The second one is a Moore 1440 with a supplementary small angle divider.
The 2 indexing tables have been transported from SMD to LNE in March 2003. Measurements were carried out by LNE on both indexing tables and are finished. The indexing tables were transported to SMD in November 2003. Measurements at SMD were planned in spring 2004 but are not finished yet because there are problems with the autocollimator. The autocollimator is actually under repair and recalibration after repair. Measurements at SMD are planned now for autumn 2004.