More and more I have been paying attention to metric measurements and wonder how it is better. It appears to have some short comings.
I first started seeing this on full extension slide schematics. Almost all hole locations are on fractions of a mm.
For example hole locations are located a distant of 4.4mm, 4.6 mm, 6.4 mm, 34.3mm and so on. And then the width of the whole thing is 1/2".
Could those holes not be at 4,6,or 34mm??? Why the fractions of a mm. Can you actually measure or see markings on a rule that are at 10ths of a mm? FWIW a tenth of a mm is slightly under 4 thousands of an inch. There would be 100 marks in a centimeter.
Now you might say that is an odd case but take Leigh Jigs DT instructions to upgrade. Drill hole at 4.37mm, WHAT? And drill the hole diameter at 3.57mm. Seriously, has any one ever seen a drill diameter of 3.57mm?
And then there are threaded inserts to accept 5/16" coarse thread bolts. Drill pilot hole with 11mm diameter bit. In so much that you want to work with imperial sized bolts, couldn't they have just said drill pilot hole at 7/16"?