Here is a cool tool that I made to measure corner radius. When I draw from an existing object, especially if it requires attachments, extra parts, or a remake, guessing the corner radius can be challenging. I use this toolset to get the information I need. I've included the .pdf file that you can download if you want to create your own.
Here is the file for the mm scale toolset
Fillet_finder_woodize
.pdf
Download PDF • 32KB