How to cut nut slots to the perfect depth every time

Optimal depth of guitar nut slots nut slot depth But you see lots of nut making instructions saying that the slots should only be about half a string diameter deep Indeed Dan Erlewine has said nut slot height The nut slots were cut very deep and now with the drier winter air, the strings were just touching the top of the first fret What I need to do

nuts and bolts slot HONJIE M6 T-Slot Nut,Black Oxide Finish,Grade ,14 Threads,Slot Width 8mm,Slot Depth 4mm,Total Depth 10mm,Pack of 5 : : Home Improvement