Different type of shaft key (Dutch Key)

[Toolmaker51]

One of the advantages of the Dutch Keys is that when you don't have a shoulder the axial location is tied to the thread, at least within the pitch of the screw and it is usually obvious if you are a pitch or more out of position.

Perfectly true Tony. I'd point out that difficulty isn't prevalent in careful work.
We find Dutch Keys/ Screw Keys infuriating when the drilling and tapping was not so carefully done. Most often is substitution of tap drill sizes, and/or whether drilling - tapping were held within decent perpendicularity. I suspect many hand done with a portable drill, which also means hole centerline may not be precise junction of shaft and bore.
The shop joke was "that machine is impersonating so and so, [a mechanic] sounds just like him!".
One soon leaned to punch mark orientation BEFORE teardown.