Share Email Facebook Twitter LinkedIn To Change Shaft Calculation Properties (AutoCAD Mechanical Toolset) At the Command prompt, enter AMOPTIONS. In the Options dialog box, select the AM:Calculation tab. In the Shaft Calculator section of the AM:Calculation tab, make the necessary entries, and choose OK. Related Concepts About Shaft Calculations (AutoCAD Mechanical Toolset) Related Tasks Workflow: Perform a Shaft Calculation (AutoCAD Mechanical Toolset) Related Reference Commands for Screw and Shaft Calculations (AutoCAD Mechanical Toolset)