[AdamHeard]

I'd suggest that however you start, end with a reamer.

1/2" shaft is something you'll probably be working with for a long time (And 3/8" for that matter), so you really should get the equipment to make the appropriate hub.

I suggest you actually get a .501 reamer, that's what we use and it works just fine.

Assuming you don't have them already, a .376 reamer and a broach set to put a 1/8" keyway in both 3/8" and 1/2" would be a very good investment.