That depends on how precise you need the hole and how well your mill is set up. Also boring a hole to size is a bit of a fiddly process and takes time setting up and checking.
Phil
PS: I think the OP may have been milling the circles as a check of mill performance, 0.012" out of round on a 1" hole needs looking at.
Originally Posted by wwendorf  Trying to mill a hole is just too imprecise.
Wade |