mtco wrote:

This is the ASCII-art drawing I said I was going to post. (Previous
attempts using HTML formatting produced garbled messages--reverting to
plain ASCII. View the diagram below in fixed width font.)

------------ --- shower drain strainer
| | --- small tabs bent to point downward
___ ___
'--... ...--'
||| ||| --- Middle ring: black rubber?/plastic? gasket?
| | | | --- Outer ring: PVC shower drain
| |
| | --- Inner ring: PVC drain pipe
| |

Note: tops of drain pipe and gasket? too high, interfering with
the "tabs" on the strainer



The black rubber ring is the seal between pipe and drain fitting.
It can be driven further down into the annular space.
You can use a tool like a thinwall cylinder or argh a blunt
screwdriver. But if it doesn't move fairly easily, there
may be too much friction built up.

Jim