I’m old enough not to care. I genuinely love the international scientific units. SI units for the lovers of physics and other things of tangible production. That said I have always been immersed in the American system of inches and feet. It’s mathematically a pain in the ass. Being immersed in the American system I’m fluent in it. I once work for a company and we were not in the field laying sewer pipe but at the shop doing oil changes on all of the company trucks. I whipped out my trusty 15mm socket and had my truck drained. Every one else no way am I using a metric socket on my Chevrolet I will wait til the old guy gets here he has a 19/32 socket he bought especially for oil changes. Impossible to convince them Chevrolet has been using metric bolts since 1980.
Btw 5/16 is almost exactly 8mm. I would run 7mm seam because I bet that is already marked on the machine