Join our CAD community forums where over 25,000 users interact to solve day to day problems and share ideas. We encourage you to visit, invite you to participate and look forward to your input and opinions. Acrobat 3D, AutoCAD, Catia, Inventor, IronCAD, Creo, Pro/ENGINEER, Solid Edge, SolidWorks, and others.
Go to C:\Program Files\Autodesk\Inventor x\Design Data\. You will find
Thread.xls. Edit the spreadsheet and add your customized thread. Make sure make a copy of the original spreadsheet, in case of faulty edit.