Use a reamer, like this one:
http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=61815556
The process is to drill (or bore) the hole slightly undersize, by a few thousandths, then to use the reamer to open up the hole to the precise diameter.
I'm sure others will jump in here with more precise instructions.
And MSC also sells drill bits larger than 1/2". They used to have a discount for FRC teams, but I don't know if that is still the case.
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Team 5148 - 2014 Wisconsin Regional Rookie All-Stars!!
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