Plastic pipe reamer. 2:32 video:
https://www.youtube.com/watch?v=tvTZHp8cF7c
More: https://www.reedmfgco.com/en/product...tting-reamers/
Previously:
https://www.homemadetools.net/forum/...amer-gif-81500
https://www.homemadetools.net/forum/...370#post161818
