That’s a mixed fraction in a foreign units System instead of a number. (Screw sizes are integers here)
Edit: we also use 1 1/3 instead of 1-1/3 in germany, making your way of writing it down more difficult to read.
Both are used and acceptable ways to write it in the US.
Also, are your screw size integers based on any units at all? If so it’s just another metric vs standard argument, and if not, it’s even less intuitive than even inches, because it’s just a case where one just needs to already know and be familiar with that sizing system, like shoe sizes or something.
That’s a mixed fraction in a foreign units System instead of a number. (Screw sizes are integers here) Edit: we also use 1 1/3 instead of 1-1/3 in germany, making your way of writing it down more difficult to read.
Both are used and acceptable ways to write it in the US.
Also, are your screw size integers based on any units at all? If so it’s just another metric vs standard argument, and if not, it’s even less intuitive than even inches, because it’s just a case where one just needs to already know and be familiar with that sizing system, like shoe sizes or something.