Original sentence: During his retirement, he was asked to join the Avogadro project to craft a silicon sphere with high smoothness, as automated machining does not match his precision
Edited sentence: He is the master optician of the Avogadro project, an international effort to define the Avogadro constant with maximum precision.He was asked to join the project from retirement as it was deemed that his expertise and craftsmanship were essential for the success of the project.Leistner has made his career in the precision crafting of specialized optics.Leistner is in his seventies and has not found an apprentice who can match his precision.Once he retires from the project, the Avogadro team hopes that machines will have advanced sufficiently to match Leistner's capabilities.The Avogadro project needed a silicon sphere made to as high a precision as possible.The research team searched the world for manufacturing options and found Leistner's precision in handcrafting spheres superior to any machine