I have had many trial and errors in putting handles in and some of this info (even in metric) would have helped me and will help me in the future I am sure
Time to move into the 20th century Poncho!
I am afraid it is to late for me
I have to many imperial tape measures and different types of rulers to start buying them again
I also collect brick rulers along with other masonry tools and all of our blueprints are in imperial as well
I just enjoy putting handles in axes and different types of hammers especially brick hammers