Hello, Thank You for your project in freelancer.
You know have some issues in this conversion, because if it is a precision dimension, you will have issues when build your part in inches.
Let me know about your project, I have a team that can handle fast for you ans deliver in Autocad format, and I also have experience and workk with both units.
PLease contact me if you feel interested,
I HAVE MORE THAN 10 YEARS WITH MECHANICAL DESIGN, AND YOUR DRAWINGS NEED TO BE ACCORDINNGLY ISO.
Thank You !