Direct reading micrometer for sine-bar elevation

摘要

The combination of a sine-bar and micrometer for directly reading angular displacement of the sine-bar, the micrometer being comprised of a barrel having a curvilinear index line with axial calibration in degrees and displaced from rotation of an extension screw of uniform pitch, and a thimble with circumferential calibrations in minutes and rotating with the said extension screw to be revolved in reference to said curvilinear index line and thereby extended in decreasing amounts corresponding to the height dimensions required in order to establish sine-bar angularity, and with curvilinear vernier calibrations parallel to said curvilinear index line for readings in seconds as well as degrees and minutes.