The technology of involutes tooth profile measurement for master gear is important and difficult in its all precision indexes.The double-disc measuring apparatus of involutes tooth profile was provided with high accuracy.The principle of the measuring apparatus was introduced and analyzes the feasibility of "The Transmission lever of no hysteretic error"which was used in the Measuring Apparatus was analyzed.In conclusion
it was proved very sensitive to micro-error and can feel content to the measuring apparatus of involutes tooth profile in benchmark step.Benchmark.