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¤¤¤¤¤☆☆☆☆☆☆☆○○○○○☆☆☆☆☆☆¤¤¤¤¤¤¤In case of a micrometer screw gauge, the backlash error is theerror in measurement due to backlsh of the internal gears. In a pair of meshing gears, the distance between tooth space and tooth thickness is called as backlash.
Black lash error in the observation caused to wear and tear of thread of the screw observed while reversing the direction of rotation of the thimble where the tip of the screw does not stat moving in the opposite direction at once but remains stationary for a part of rotation.
Avoid black lash error =while taking measurement screw should be rotated in one direction