The Shulchan Aruch says that when one cuts a sharp food with a knife, it makes the flavor in the knife "BeEin" - as if it were visible (and not just a "taste").
Is that only for the laws of "Nat Bar Nat" or also for the laws of waiting six hours?
The Darkei Teshuvah YD 89:42, (paragraph beginning ועיין) discusses this question in depth, and quotes various sources in both directions. See also here, final paragraph, which seems to understand the conclusion of the Darkei Teshuva to be that it is permitted. This is certainly the Minhag (and the standard Pesak), as can be seen from here (second comment) and here.