[Mik325tds]

Starting with a 7/16" drill, slow rpms and good cutting oil, I then used a 1/2" reamer as my final size due to lack of a larger reamer. The recommended new diameter is 9/16".
The hole is pretty long so it takes a bit of patience to do this job. Half way through I took a picture to check my direction. As you can see, I deviated a little bit which doesn't seem to be a problem though.
Definitely wear eye protection as hot metal shavings will fall down on you. Very unpleasant.