1968 plumbing standards

[Scott Peterson]

I discovered this weekend that the tub trap in my house (1968) uses a
thread pitch no longer seen. The old strainer fitting is the same
diameter currently called "fine" pitch, but the threads are slightly
different. Nobody (including Hippo Hardware) seems to have anything
that will fit it.

Has anyone else replaced their tub strainer (in, say, the last
decade) without replacing the whole overflow/drain assembly? Where
did you find the parts with the right thread?

I can solve this by replacing the whole assembly from underneath
(assuming the opening in the floor is big enough to get at all the
parts), but that's an adventure I'd rather avoid.

--- sdp