a year ago I helped my son redo his metal washer drain to PVC plastic and used a male threaded fitting to screw into existing metal stack.----NOW--- we are redoing the stack eliminating that line and extending it to main stack which will also be PVC. (there are issues only this will fix further up).
Snapping the stack right above floor level to no-hub cast to PVC. this washer drain was glued as close as possible to another tee coming from another sink.
I am planning on cracking the cast off the threaded part or snapping just above and below it and unscrewing it,,,,then screwing a female thread X glue fitting on with Teflon tape and continuing on 8 to 10 more inches to drop into stack with a long sweep fitting.
Either that or I have to cut both lines before the tee,,couple on short pipes, and new tee then drop into stack.
Is screwing female and male fittings back to back acceptable(which is much easier)??????