Thank you for starting this thread @MWJB , a good idea to separate from the v60 discussion.
So there seem to be two main advantages/ goals to sifting. 1 is being able to objectively compare grind size and ‘callibrate’ two (or more) different grinders for the same brew method. 2 is being able to compare grind size distribution.
One of my comments on the v60 thread was about understanding the principle of these comparisons. It is easy to follow an instruction and get a result, but it is another thing to understand the ‘why’. This is less relevant for the calibration of grinders, but when then looking at grind size distribution and discussing in terms of standard deviations the more one understands the fundamental principles the more one will get out of it and be able to objectively interpret and use that data more.
I don’t know if this is along the same lines as your example of kruve vs ASTM, but I seems easy to interpret that as the two different sifting scales correlating - I.e. x Kruve = y ASTM - without understanding the principles behind it.
I am pretty certain I am going to get a kruve, but it’ll have to be in the new year.
@JJJJJamie - where did you order your kruve from? Will be interested to hear how you get on with it.
You can buy the 400 separately, but you might not need to depending on use.