In article ,
DougC wrote:

Is there such a thing? The usual places show nothing of the kind.

Countersunk-head screws fit flush with the surface of course, but
another aspect of them is that they stay centered in the holes. Is there
a nut with a conical contact area to fit similarly?

Check the lug nuts on your car....

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.