On 02/26/2017 11:27 AM, trader_4 wrote:
....

It is a water seal. Look at the link to a diagram that I
posted. A typical sink has two drain paths, one that you're
talking about from the bowl that the water usually goes down.
The other is from inside the sink, between it's inner and outer
layers, whereby the overflow is routed. The sink drain has
holes in it so that it's open in that gap inside the sink,
below the hole, so that the overflow water can run into it.
....

OK, I can see a misreading of what was I said, but I repeat the threads
on the jamb nut are _not_ the water seal; they're merely mechanical to
apply the force to seat the drainset into the plumbers putty
sufficiently to fill all the voids.

I stand by the previous that if it's leaking there, either there wasn't
sufficient putty used or there's something else preventing it from fully
filling the voids; a non-tapered thread cannot be a water seal and isn't
intended to be the seal in this location.

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