I made a 70mm socket for my bulkheads (1.5" sched 40) out of 3" pvc or so. Cut a strip of it off the end, shorten it and glue it back into the end (to double the wall thickness) and with a printed out guide dremelled the flats.
At the other end drill a hole through both walls and stick like a 3/4" bit of pipe for extra leverage.
Real handy when you can't get anything much longer than the bulkhead is wide deep into a cavity.
Could probably 3d print a socket end to glue onto a bit of large pipe too, since it isn't that much force you need to put on these things (just can be really inconveniently located).