I'm fairly sure this is just a compression seal. There's a rubber gasket
that gets squashed tight when you crank that nut down onto the trap. If the
gasket is old and hard, it might leak.

"Leo" wrote in message ...
How do you seal the connection between the drain pipe under a sink and the
trap? I took this apart to fix a slow draining system... with that
problem
solved now I have another.

The drain pipe fits into the trap and a large nut threads onto the trap.
By
the by, this home was built in the early seventies and this is probably
original stuff.

Thanks.