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Description: | One of a set of 8 machine finish comparitor blocks in black mock-leather holder by Rubert & Co. Ltd. Scale no. 122 'Reaming and Drilling'. Red frontage with 4 drilling and 4 reaming comparators. Full description on reverse including text "Both drilling and reaming frequently produce surfaces which not only lack the uniformity of lead marks, but also contain deep and widely spaced ridges superimposed on the primary texture. On drilling there are also sometimes helical scratches with a very wide pitch resulting from the withdrawal of the drill. These scratches can be seen on some drilled specimens. In order to provide a representative illustration we have chosen two of each farily regular surfaces and two of each extremely bad ones, the numerical assessment of the latter being very difficult and rather vague when designated in CLA. Reliable assessments can only be made by measuring the deepest scratch mark (max. depth Rt).
Acquisition source: Natural Philosophy Metrology Laboratory | License: | http://www.abdn.ac.uk/historic/Copyright_terms_conditions.shtml | Publisher: | ABDNP University of Aberdeen, Natural Philosophy Collection of Historical Scientific Instruments | Rights holder: | 47718 | Temporal: | 1960-1975 | Source: | University of Aberdeen | Creator: | Rubert & Co. Ltd. Precision Engineers | Identifier: | http://calms.abdn.ac.uk/Geology/dserve.e... | Go to resource |
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