Engineering Metrology

accuracy accurate adjusted alignment telescope angular applied auto-collimator beam block calibration calliper centre Chapter checked circle clinometer collimating lens collimator comparator components courtesy of Messrs cylinder dial indicator dimensions dividing head edge effective diameter end bar engineering errors eyepiece faces fitted fringes gear glass graticule grinding Hilger & Watts hole horizontal illustrated in plate inch indicator instrument interferometer jig borer lapped length limit line standard magnification manufacture measuring machine ment method metrology microscope minor diameter mounted obtained optical axis optical flat optical micrometer pantograph parallel pitch plane plug position precision principle projector protractor radius range reading reflected reflector rollers rotation scale screw gauge screw threads shown in fig sine bar slip gauges specification spindle square steel straight straightedge stylus suitable surface plate taper testing theodolite thread form tolerances Troughton & Simms tube values variations vertical Watts Ltd wavelength wires