Drywall holesaw.
https://diqn32j8nouaz.cloudfront.net...ck_holesaw.jpg
Previously:
https://www.homemadetools.net/forum/...484#post151173
https://www.homemadetools.net/forum/...455#post142764
https://www.homemadetools.net/forum/...576#post132469
https://www.homemadetools.net/forum/...7815#post86291
https://www.homemadetools.net/forum/...115#post125913
