Hammer and center punch method
Success! I decided to try the hammer and center punch method before fabricating an airstream black hole wrench because I didn't have any angle iron lying around. The center punch method worked in this case. The black abs flange moved about an 1/8 inch with each tap of the hammer. So quite a few taps were require. Eventually the punch actually rounded out the taps in the flange. So I had to cut new tabs in the flange with a small hand saw. The black abs flange in this case had plastic threads.
“Complications arose, ensued, were overcome...savvy?”
- Captain Jack Sparrow